Manually unwind method prologue

# Conflicts:
#	Makefile
#	src/arguments.cpp
#	src/arguments.h
#	src/flightRecorder.cpp

.github/workflows/cpp.yml

@@ -0,0 +1,21 @@
+name: C++ CI
+
+on:
+  - push
+  - pull_request
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - uses: actions/setup-java@v2.1.0
+        with:
+          distribution: "adopt"
+          java-version: "11"
+      - run: sudo sysctl kernel.perf_event_paranoid=1
+      - run: make
+      - run: make test
+      - uses: actions/upload-artifact@v2
+        with:
+          path: build/

.gitignore

@@ -1,6 +1,7 @@
 /build/
 /nbproject/
 /out/
+/target/
 /.idea/
 /test/*.class
 .vscode

.travis.yml

@@ -1,6 +1,6 @@
 language: cpp
 
-dist: precise
+dist: bionic
 
 sudo: required
 

CHANGELOG.md

@@ -1,21 +1,171 @@
 # Changelog
 
-## [2.0-b1] - Early access
+## [2.9] - 2022-11-27
+
+### Features
+ - Java Heap leak profiler
+ - `meminfo` command to print profiler's memory usage
+ - Profiler API with embedded agent as a Maven artifact
+
+### Improvements
+ - `--include`/`--exclude` options in the FlameGraph converter
+ - `--simple` and `--dot` options in jfr2flame converter
+ - An option for agressive recovery of `[unknown_Java]` stack traces
+ - Do not truncate signatures in collapsed format
+ - Display inlined frames under a runtime stub
+
+### Bug fixes
+ - Profiler did not work with Homebrew JDK
+ - Fixed allocation profiling on Zing
+ - Various `jfrsync` fixes
+ - Symbol parsing fixes
+ - Attaching to a container on Linux 3.x could fail
+
+## [2.8.3] - 2022-07-16
+
+### Improvements
+ - Support virtualized ARM64 macOS
+ - A switch to generate auxiliary events by async-profiler or FlightRecorder in jfrsync mode
+
+### Bug fixes
+ - Could not recreate perf_events after the first failure
+ - Handle different versions of Zing properly
+ - Do not call System.loadLibrary, when libasyncProfiler is preloaded
+
+## [2.8.2] - 2022-07-13
+
+### Bug fixes
+ - The same .so works with glibc and musl
+ - dlopen hook did not work on Arch Linux
+ - Fixed JDK 7 crash
+ - Fixed CPU profiling on Zing
+
+### Changes
+ - Mark interpreted frames with `_[0]` in collapsed output
+ - Double click selects a method name on a flame graph
+
+## [2.8.1] - 2022-06-10
+
+### Improvements
+ - JFR to pprof converter (contributed by @NeQuissimus)
+ - JFR converter improvements: time range, collapsed output, pattern highlighting
+ - `%n` pattern in file names; limit number of output files
+ - `--lib` to customize profiler library path in a container
+ - `profiler.sh list` command now works without PID
+
+### Bug fixes
+ - Fixed crashes related to continuous profiling
+ - Fixed Alpine/musl compatibility issues
+ - Fixed incomplete collapsed output due to weird locale settings
+ - Workaround for JDK-8185348
+
+## [2.8] - 2022-05-09
+
+### Features
+ - Mark top methods as interpreted, compiled (C1/C2), or inlined
+ - JVM TI based allocation profiling for JDK 11+
+ - Embedded HTTP management server
+
+### Improvements
+ - Re-implemented stack recovery for better reliability
+ - Add `loglevel` argument
+ - Do not mmap perf page in `--all-user` mode
+ - Distinguish runnable/sleeping threads in OpenJ9 wall-clock profiler
+ - `--cpu` converter option to extract CPU profile from the wall-clock output
+
+## [2.7] - 2022-02-14
+
+### Features
+ - Experimental support for OpenJ9 VM
+ - DWARF stack unwinding
+
+### Improvements
+ - Better handling of VM threads (fixed missing JIT threads)
+ - More reliable recovery from `not_walkable` AGCT failures
+ - Do not accept unknown agent arguments
+
+## [2.6] - 2022-01-09
+
+### Features
+ - Continuous profiling; `loop` and `timeout` options
+
+### Improvements
+ - Reliability improvements: avoid certain crashes and deadlocks
+ - Smaller and faster agent library
+ - Minor `jfr` and `jfrsync` enhancements (see the commit log)
+
+## [2.5.1] - 2021-12-05
+
+### Bug fixes
+ - Prevent early unloading of libasyncProfiler.so
+ - Read kernel symbols only for perf_events
+ - Escape backslashes in flame graphs
+ - Avoid duplicate categories in `jfrsync` mode
+ - Fixed stack overflow in RedefineClasses
+ - Fixed deadlock when flushing JFR
+
+### Improvements
+ - Support OpenJDK C++ Interpreter (aka Zero)
+ - Allow reading incomplete JFR recordings
+
+## [2.5] - 2021-10-01
+
+### Features
+ - macOS/ARM64 (aka Apple M1) port
+ - PPC64LE port (contributed by @ghaug)
+ - Profile low-privileged processes with perf_events (contributed by @Jongy)
+ - Raw PMU events; kprobes & uprobes
+ - Dump results in the middle of profiling session
+ - Chunked JFR; support JFR files larger than 2 GB
+ - Integrate async-profiler events with JDK Flight Recordings
+
+### Improvements
+ - Use RDTSC for JFR timestamps when possible
+ - Show line numbers and bci in Flame Graphs
+ - jfr2flame can produce Allocation and Lock flame graphs
+ - Flame Graph title depends on the event and `--total`
+ - Include profiler logs and native library list in JFR output
+ - Lock profiling no longer requires JVM symbols
+ - Better container support
+ - Native function profiler can count the specified argument
+ - An option to group threads by scheduling policy
+ - An option to prepend library name to native symbols
+
+### Notes
+ - macOS build is provided as a fat binary that works both on x86-64 and ARM64
+ - 32-bit binaries are no longer shipped. It is still possible to build them from sources
+ - Dropped JDK 6 support (may still work though)
+
+## [2.0] - 2021-03-14
 
 ### Features
  - Profile multiple events together (cpu + alloc + lock)
  - HTML 5 Flame Graphs: faster rendering, smaller size
  - JFR v2 output format, compatible with FlightRecorder API
+ - JFR to Flame Graph converter
  - Automatically turn profiling on/off at `--begin`/`--end` functions
- - Time-to-safepoint profiling
+ - Time-to-safepoint profiling: `--ttsp`
 
 ### Improvements
  - Unlimited frame buffer. Removed `-b` option and 64K stack traces limit
- - Record CPU load in JFR format
+ - Additional JFR events: OS, CPU, and JVM information; CPU load
+ - Record bytecode indices / line numbers
+ - Native stack traces for Java events
+ - Improved CLI experience
+ - Better error handling; an option to log warnings/errors to a dedicated stream
+ - Reduced the amount of unknown stack traces
 
 ### Changes
  - Removed non-ASL code. No more CDDL license
 
+## [1.8.4] - 2021-02-24
+
+### Improvements
+ - Smaller and faster agent library
+
+### Bug fixes
+ - Fixed JDK 7 crash during wall-clock profiling
+
 ## [1.8.3] - 2021-01-06
 
 ### Improvements

Makefile

@@ -1,6 +1,4 @@
-PROFILER_VERSION=2.0-b1
-JATTACH_VERSION=1.5
-JAVAC_RELEASE_VERSION=6
+PROFILER_VERSION=2.9-bpf
 
 PACKAGE_NAME=async-profiler-$(PROFILER_VERSION)-$(OS_TAG)-$(ARCH_TAG)
 PACKAGE_DIR=/tmp/$(PACKAGE_NAME)
@@ -11,16 +9,21 @@ JATTACH=jattach
 API_JAR=async-profiler.jar
 CONVERTER_JAR=converter.jar
 
-CFLAGS=-O3 -fno-omit-frame-pointer -fvisibility=hidden
+CFLAGS=-O3
 CXXFLAGS=-O3 -fno-omit-frame-pointer -fvisibility=hidden
-INCLUDES=-I$(JAVA_HOME)/include
+INCLUDES=-I$(JAVA_HOME)/include -Isrc/res -Isrc/helper
 LIBS=-ldl -lpthread
+MERGE=true
 
 JAVAC=$(JAVA_HOME)/bin/javac
 JAR=$(JAVA_HOME)/bin/jar
+JAVA_TARGET=7
+JAVAC_OPTIONS=-source $(JAVA_TARGET) -target $(JAVA_TARGET) -Xlint:-options
 
 SOURCES := $(wildcard src/*.cpp)
-HEADERS := $(wildcard src/*.h)
+HEADERS := $(wildcard src/*.h src/fdtransfer/*.h)
+RESOURCES := $(wildcard src/res/*)
+JAVA_HELPER_CLASSES := $(wildcard src/helper/one/profiler/*.class)
 API_SOURCES := $(wildcard src/api/one/profiler/*.java)
 CONVERTER_SOURCES := $(shell find src/converter -name '*.java')
 
@@ -29,17 +32,33 @@ ifeq ($(JAVA_HOME),)
 endif
 
 OS:=$(shell uname -s)
-ifeq ($(OS), Darwin)
-  CXXFLAGS += -D_XOPEN_SOURCE -D_DARWIN_C_SOURCE
+ifeq ($(OS),Darwin)
+  CXXFLAGS += -D_XOPEN_SOURCE -D_DARWIN_C_SOURCE -Wl,-rpath,@executable_path/../lib -Wl,-rpath,@executable_path/../lib/server
   INCLUDES += -I$(JAVA_HOME)/include/darwin
+  FDTRANSFER_BIN=
   SOEXT=dylib
+  PACKAGE_EXT=zip
   OS_TAG=macos
+  ifeq ($(FAT_BINARY),true)
+    FAT_BINARY_FLAGS=-arch x86_64 -arch arm64 -mmacos-version-min=10.12
+    CFLAGS += $(FAT_BINARY_FLAGS)
+    CXXFLAGS += $(FAT_BINARY_FLAGS)
+    PACKAGE_NAME=async-profiler-$(PROFILER_VERSION)-$(OS_TAG)
+    MERGE=false
+  endif
 else
+  CXXFLAGS += -Wl,-z,defs
+  ifeq ($(MERGE),true)
+    CXXFLAGS += -fwhole-program
+  endif
   LIBS += -lrt
   INCLUDES += -I$(JAVA_HOME)/include/linux
+  FDTRANSFER_BIN=build/fdtransfer
   SOEXT=so
+  PACKAGE_EXT=tar.gz
   ifeq ($(findstring musl,$(shell ldd /bin/ls)),musl)
     OS_TAG=linux-musl
+    CXXFLAGS += -D__musl__
   else
     OS_TAG=linux
   endif
@@ -50,63 +69,103 @@ ifeq ($(ARCH),x86_64)
   ARCH_TAG=x64
 else
   ifeq ($(findstring arm,$(ARCH)),arm)
-    ARCH_TAG=arm
+    ifeq ($(findstring 64,$(ARCH)),64)
+      ARCH_TAG=arm64
+    else
+      ARCH_TAG=arm32
+    endif
   else
     ifeq ($(findstring aarch64,$(ARCH)),aarch64)
-      ARCH_TAG=aarch64
+      ARCH_TAG=arm64
     else
-      ARCH_TAG=x86
+      ifeq ($(ARCH),ppc64le)
+        ARCH_TAG=ppc64le
+      else
+        ARCH_TAG=x86
+      endif
     endif
   endif
 endif
 
+ifneq ($(ARCH),ppc64le)
+  ifneq ($(ARCH_TAG),arm32)
+    CXXFLAGS += -momit-leaf-frame-pointer
+  endif
+endif
 
-.PHONY: all release test clean
 
-all: build build/$(LIB_PROFILER) build/$(JATTACH) build/$(API_JAR) build/$(CONVERTER_JAR)
+.PHONY: all release test native clean
 
-release: build $(PACKAGE_NAME).tar.gz
+all: build build/$(LIB_PROFILER) build/$(JATTACH) $(FDTRANSFER_BIN) build/$(API_JAR) build/$(CONVERTER_JAR)
 
-$(PACKAGE_NAME).tar.gz: build/$(LIB_PROFILER) build/$(JATTACH) \
-                        build/$(API_JAR) build/$(CONVERTER_JAR) \
-                        profiler.sh LICENSE *.md
+release: build $(PACKAGE_NAME).$(PACKAGE_EXT)
+
+$(PACKAGE_NAME).tar.gz: $(PACKAGE_DIR)
+	tar czf $@ -C $(PACKAGE_DIR)/.. $(PACKAGE_NAME)
+	rm -r $(PACKAGE_DIR)
+
+$(PACKAGE_NAME).zip: $(PACKAGE_DIR)
+	codesign -s "Developer ID" -o runtime --timestamp -v $(PACKAGE_DIR)/build/$(JATTACH) $(PACKAGE_DIR)/build/$(LIB_PROFILER_SO)
+	ditto -c -k --keepParent $(PACKAGE_DIR) $@
+	rm -r $(PACKAGE_DIR)
+
+$(PACKAGE_DIR): build/$(LIB_PROFILER) build/$(JATTACH) $(FDTRANSFER_BIN) \
+                build/$(API_JAR) build/$(CONVERTER_JAR) \
+                profiler.sh LICENSE *.md
 	mkdir -p $(PACKAGE_DIR)
 	cp -RP build profiler.sh LICENSE *.md $(PACKAGE_DIR)
 	chmod -R 755 $(PACKAGE_DIR)
 	chmod 644 $(PACKAGE_DIR)/LICENSE $(PACKAGE_DIR)/*.md $(PACKAGE_DIR)/build/*.jar
-	tar cvzf $@ -C $(PACKAGE_DIR)/.. $(PACKAGE_NAME)
-	rm -r $(PACKAGE_DIR)
 
 %.$(SOEXT): %.so
+	rm -f $@
 	-ln -s $(<F) $@
 
 build:
 	mkdir -p build
 
-build/$(LIB_PROFILER_SO): $(SOURCES) $(HEADERS)
+build/$(LIB_PROFILER_SO): $(SOURCES) $(HEADERS) $(RESOURCES) $(JAVA_HELPER_CLASSES)
+ifeq ($(MERGE),true)
+	for f in src/*.cpp; do echo '#include "'$$f'"'; done |\
+	$(CXX) $(CXXFLAGS) -DPROFILER_VERSION=\"$(PROFILER_VERSION)\" $(INCLUDES) -fPIC -shared -o $@ -xc++ - $(LIBS)
+else
 	$(CXX) $(CXXFLAGS) -DPROFILER_VERSION=\"$(PROFILER_VERSION)\" $(INCLUDES) -fPIC -shared -o $@ $(SOURCES) $(LIBS)
+endif
 
-build/$(JATTACH): src/jattach/jattach.c
-	$(CC) $(CFLAGS) -DJATTACH_VERSION=\"$(JATTACH_VERSION)\" -o $@ $^
+build/$(JATTACH): src/jattach/*.c src/jattach/*.h
+	$(CC) $(CFLAGS) -DJATTACH_VERSION=\"$(PROFILER_VERSION)-ap\" -o $@ src/jattach/*.c
+
+build/fdtransfer: src/fdtransfer/*.cpp src/fdtransfer/*.h src/jattach/psutil.c src/jattach/psutil.h
+	$(CXX) $(CFLAGS) -o $@ src/fdtransfer/*.cpp src/jattach/psutil.c
 
 build/$(API_JAR): $(API_SOURCES)
 	mkdir -p build/api
-	$(JAVAC) -source $(JAVAC_RELEASE_VERSION) -target $(JAVAC_RELEASE_VERSION) -d build/api $^
-	$(JAR) cvf $@ -C build/api .
+	$(JAVAC) $(JAVAC_OPTIONS) -d build/api $^
+	$(JAR) cf $@ -C build/api .
 	$(RM) -r build/api
 
-build/$(CONVERTER_JAR): $(CONVERTER_SOURCES) src/converter/MANIFEST.MF
+build/$(CONVERTER_JAR): $(CONVERTER_SOURCES) $(RESOURCES)
 	mkdir -p build/converter
-	$(JAVAC) -source 7 -target 7 -d build/converter $(CONVERTER_SOURCES)
-	$(JAR) cvfm $@ src/converter/MANIFEST.MF -C build/converter .
+	$(JAVAC) $(JAVAC_OPTIONS) -d build/converter $(CONVERTER_SOURCES)
+	$(JAR) cfe $@ Main -C build/converter . -C src/res .
 	$(RM) -r build/converter
 
+%.class: %.java
+	$(JAVAC) $(JAVAC_OPTIONS) -g:none $^
+
 test: all
 	test/smoke-test.sh
 	test/thread-smoke-test.sh
 	test/alloc-smoke-test.sh
 	test/load-library-test.sh
+	test/fdtransfer-smoke-test.sh
 	echo "All tests passed"
 
+native:
+	mkdir -p native/linux-x64 native/linux-arm64 native/macos
+	tar xfO async-profiler-$(PROFILER_VERSION)-linux-x64.tar.gz */build/libasyncProfiler.so > native/linux-x64/libasyncProfiler.so
+	tar xfO async-profiler-$(PROFILER_VERSION)-linux-arm64.tar.gz */build/libasyncProfiler.so > native/linux-arm64/libasyncProfiler.so
+	unzip -p async-profiler-$(PROFILER_VERSION)-macos.zip */build/libasyncProfiler.so > native/macos/libasyncProfiler.so
+
 clean:
 	$(RM) -r build

README.md

@@ -1,7 +1,5 @@
 # async-profiler
 
-[![Build Status](https://travis-ci.org/jvm-profiling-tools/async-profiler.svg?branch=master)](https://travis-ci.org/jvm-profiling-tools/async-profiler)
-
 This project is a low overhead sampling profiler for Java
 that does not suffer from [Safepoint bias problem](http://psy-lob-saw.blogspot.ru/2016/02/why-most-sampling-java-profilers-are.html).
 It features HotSpot-specific APIs to collect stack traces
@@ -13,41 +11,626 @@ async-profiler can trace the following kinds of events:
  - Hardware and Software performance counters like cache misses, branch misses, page faults, context switches etc.
  - Allocations in Java Heap
  - Contented lock attempts, including both Java object monitors and ReentrantLocks
- 
-## Usage
 
-See our [Wiki](https://github.com/jvm-profiling-tools/async-profiler/wiki) or [3 hours playlist](https://www.youtube.com/playlist?list=PLNCLTEx3B8h4Yo_WvKWdLvI9mj1XpTKBr) to learn about all set of features. 
+See our [Wiki](https://github.com/jvm-profiling-tools/async-profiler/wiki) or
+[3 hours playlist](https://www.youtube.com/playlist?list=PLNCLTEx3B8h4Yo_WvKWdLvI9mj1XpTKBr)
+to learn about all features. 
 
 ## Download
 
-Latest release (1.8.3):
+Current release (2.9):
 
- - Linux x64 (glibc): [async-profiler-1.8.3-linux-x64.tar.gz](https://github.com/jvm-profiling-tools/async-profiler/releases/download/v1.8.3/async-profiler-1.8.3-linux-x64.tar.gz)
- - Linux x86 (glibc): [async-profiler-1.8.3-linux-x86.tar.gz](https://github.com/jvm-profiling-tools/async-profiler/releases/download/v1.8.3/async-profiler-1.8.3-linux-x86.tar.gz)
- - Linux x64 (musl): [async-profiler-1.8.3-linux-musl-x64.tar.gz](https://github.com/jvm-profiling-tools/async-profiler/releases/download/v1.8.3/async-profiler-1.8.3-linux-musl-x64.tar.gz)
- - Linux ARM: [async-profiler-1.8.3-linux-arm.tar.gz](https://github.com/jvm-profiling-tools/async-profiler/releases/download/v1.8.3/async-profiler-1.8.3-linux-arm.tar.gz)
- - Linux AArch64: [async-profiler-1.8.3-linux-aarch64.tar.gz](https://github.com/jvm-profiling-tools/async-profiler/releases/download/v1.8.3/async-profiler-1.8.3-linux-aarch64.tar.gz)
- - macOS x64: [async-profiler-1.8.3-macos-x64.tar.gz](https://github.com/jvm-profiling-tools/async-profiler/releases/download/v1.8.3/async-profiler-1.8.3-macos-x64.tar.gz)
-
-[Early access](https://github.com/jvm-profiling-tools/async-profiler/releases/tag/v2.0-b1) (2.0-b1):
-
- - Linux x64 (glibc): [async-profiler-2.0-b1-linux-x64.tar.gz](https://github.com/jvm-profiling-tools/async-profiler/releases/download/v2.0-b1/async-profiler-2.0-b1-linux-x64.tar.gz)
- - macOS x64: [async-profiler-2.0-b1-macos-x64.tar.gz](https://github.com/jvm-profiling-tools/async-profiler/releases/download/v2.0-b1/async-profiler-2.0-b1-macos-x64.tar.gz)
+ - Linux x64 (glibc): [async-profiler-2.9-linux-x64.tar.gz](https://github.com/jvm-profiling-tools/async-profiler/releases/download/v2.9/async-profiler-2.9-linux-x64.tar.gz)
+ - Linux x64 (musl): [async-profiler-2.9-linux-musl-x64.tar.gz](https://github.com/jvm-profiling-tools/async-profiler/releases/download/v2.9/async-profiler-2.9-linux-musl-x64.tar.gz)
+ - Linux arm64: [async-profiler-2.9-linux-arm64.tar.gz](https://github.com/jvm-profiling-tools/async-profiler/releases/download/v2.9/async-profiler-2.9-linux-arm64.tar.gz)
+ - macOS x64/arm64: [async-profiler-2.9-macos.zip](https://github.com/jvm-profiling-tools/async-profiler/releases/download/v2.9/async-profiler-2.9-macos.zip)
+ - Converters between profile formats: [converter.jar](https://github.com/jvm-profiling-tools/async-profiler/releases/download/v2.9/converter.jar)  
+   (JFR to Flame Graph, JFR to FlameScope, collapsed stacks to Flame Graph)
 
 [Previous releases](https://github.com/jvm-profiling-tools/async-profiler/releases)
 
+Note: async-profiler also comes bundled with IntelliJ IDEA Ultimate 2018.3 and later.
+For more information refer to [IntelliJ IDEA documentation](https://www.jetbrains.com/help/idea/cpu-and-allocation-profiling-basic-concepts.html).
+
 ## Supported platforms
 
-- **Linux** / x64 / x86 / ARM / AArch64
-- **macOS** / x64
+ - **Linux** / x64 / x86 / arm64 / arm32 / ppc64le
+ - **macOS** / x64 / arm64
 
-Note: macOS profiling is limited to user space code only.
+### Community supported builds
+
+ - **Windows** / x64 - <img src="https://upload.wikimedia.org/wikipedia/commons/9/9c/IntelliJ_IDEA_Icon.svg" width="16" height="16"/> [IntelliJ IDEA](https://www.jetbrains.com/idea/) 2021.2 and later
+ - [**ap-loader**](https://github.com/jvm-profiling-tools/ap-loader) -
+   all-in-one JAR for using async-profiler in Java programs and as a CLI tool
+
+## CPU profiling
+
+In this mode profiler collects stack trace samples that include **Java** methods,
+**native** calls, **JVM** code and **kernel** functions.
+
+The general approach is receiving call stacks generated by `perf_events`
+and matching them up with call stacks generated by `AsyncGetCallTrace`,
+in order to produce an accurate profile of both Java and native code.
+Additionally, async-profiler provides a workaround to recover stack traces
+in some [corner cases](https://bugs.openjdk.java.net/browse/JDK-8178287)
+where `AsyncGetCallTrace` fails.
+
+This approach has the following advantages compared to using `perf_events`
+directly with a Java agent that translates addresses to Java method names:
+
+* Works on older Java versions because it doesn't require
+  `-XX:+PreserveFramePointer`, which is only available in JDK 8u60 and later.
+
+* Does not introduce the performance overhead from `-XX:+PreserveFramePointer`,
+  which can in rare cases be as high as 10%.
+
+* Does not require generating a map file to map Java code addresses to method
+  names.
+
+* Works with interpreter frames.
+
+* Does not require writing out a perf.data file for further processing in
+  user space scripts.
+
+If you wish to resolve frames within `libjvm`, the [debug symbols](#installing-debug-symbols) are required.
+
+## ALLOCATION profiling
+
+Instead of detecting CPU-consuming code, the profiler can be configured
+to collect call sites where the largest amount of heap memory is allocated.
+
+async-profiler does not use intrusive techniques like bytecode instrumentation
+or expensive DTrace probes which have significant performance impact.
+It also does not affect Escape Analysis or prevent from JIT optimizations
+like allocation elimination. Only actual heap allocations are measured.
+
+The profiler features TLAB-driven sampling. It relies on HotSpot-specific
+callbacks to receive two kinds of notifications:
+ - when an object is allocated in a newly created TLAB (aqua frames in a Flame Graph);
+ - when an object is allocated on a slow path outside TLAB (brown frames).
+
+This means not each allocation is counted, but only allocations every _N_ kB,
+where _N_ is the average size of TLAB. This makes heap sampling very cheap
+and suitable for production. On the other hand, the collected data
+may be incomplete, though in practice it will often reflect the top allocation
+sources.
+
+Sampling interval can be adjusted with `--alloc` option.
+For example, `--alloc 500k` will take one sample after 500 KB of allocated
+space on average. However, intervals less than TLAB size will not take effect.
+
+The minimum supported JDK version is 7u40 where the TLAB callbacks appeared.
+
+### Installing Debug Symbols
+
+Prior to JDK 11, the allocation profiler required HotSpot debug symbols.
+Oracle JDK already has them embedded in `libjvm.so`, but in OpenJDK builds
+they are typically shipped in a separate package. For example, to install
+OpenJDK debug symbols on Debian / Ubuntu, run:
+```
+# apt install openjdk-8-dbg
+```
+or for OpenJDK 11:
+```
+# apt install openjdk-11-dbg
+```
+
+On CentOS, RHEL and some other RPM-based distributions, this could be done with
+[debuginfo-install](http://man7.org/linux/man-pages/man1/debuginfo-install.1.html) utility:
+```
+# debuginfo-install java-1.8.0-openjdk
+```
+
+On Gentoo the `icedtea` OpenJDK package can be built with the per-package setting
+`FEATURES="nostrip"` to retain symbols.
+
+The `gdb` tool can be used to verify if the debug symbols are properly installed for the `libjvm` library.
+For example on Linux:
+```
+$ gdb $JAVA_HOME/lib/server/libjvm.so -ex 'info address UseG1GC'
+```
+This command's output will either contain `Symbol "UseG1GC" is at 0xxxxx`
+or `No symbol "UseG1GC" in current context`.
+
+## Wall-clock profiling
+
+`-e wall` option tells async-profiler to sample all threads equally every given
+period of time regardless of thread status: Running, Sleeping or Blocked.
+For instance, this can be helpful when profiling application start-up time.
+
+Wall-clock profiler is most useful in per-thread mode: `-t`.
+
+Example: `./profiler.sh -e wall -t -i 5ms -f result.html 8983`
+
+## Java method profiling
+
+`-e ClassName.methodName` option instruments the given Java method
+in order to record all invocations of this method with the stack traces.
+
+Example: `-e java.util.Properties.getProperty` will profile all places
+where `getProperty` method is called from.
+
+Only non-native Java methods are supported. To profile a native method,
+use hardware breakpoint event instead, e.g. `-e Java_java_lang_Throwable_fillInStackTrace`
+
+**Be aware** that if you attach async-profiler at runtime, the first instrumentation
+of a non-native Java method may cause the [deoptimization](https://github.com/openjdk/jdk/blob/bf2e9ee9d321ed289466b2410f12ad10504d01a2/src/hotspot/share/prims/jvmtiRedefineClasses.cpp#L4092-L4096)
+of all compiled methods. The subsequent instrumentation flushes only the _dependent code_.
+
+The massive CodeCache flush doesn't occur if attaching async-profiler as an agent.
+
+Here are some useful native methods that you may want to profile:
+* ```G1CollectedHeap::humongous_obj_allocate``` - trace the _humongous allocation_ of the G1 GC,
+* ```JVM_StartThread``` - trace the new thread creation,
+* ```Java_java_lang_ClassLoader_defineClass1``` - trace class loading.
 
 ## Building
 
+Build status: [![Build Status](https://github.com/jvm-profiling-tools/async-profiler/actions/workflows/cpp.yml/badge.svg?branch=master)](https://github.com/jvm-profiling-tools/async-profiler/actions/workflows/cpp.yml)
+
 Make sure the `JAVA_HOME` environment variable points to your JDK installation,
 and then run `make`. GCC is required. After building, the profiler agent binary
 will be in the `build` subdirectory. Additionally, a small application `jattach`
 that can load the agent into the target process will also be compiled to the
-`build` subdirectory.
+`build` subdirectory. If the build fails due to
+`Source option 7 is no longer supported. Use 8 or later.`, use `make JAVA_TARGET=8`.
 
+## Basic Usage
+
+As of Linux 4.6, capturing kernel call stacks using `perf_events` from a non-root
+process requires setting two runtime variables. You can set them using
+sysctl or as follows:
+
+```
+# sysctl kernel.perf_event_paranoid=1
+# sysctl kernel.kptr_restrict=0
+```
+
+To run the agent and pass commands to it, the helper script `profiler.sh`
+is provided. A typical workflow would be to launch your Java application,
+attach the agent and start profiling, exercise your performance scenario, and
+then stop profiling. The agent's output, including the profiling results, will
+be displayed in the Java application's standard output.
+
+Example:
+
+```
+$ jps
+9234 Jps
+8983 Computey
+$ ./profiler.sh start 8983
+$ ./profiler.sh stop 8983
+```
+
+The following may be used in lieu of the `pid` (8983):
+
+ - The keyword `jps`, which will use the most recently launched Java process.
+ - The application name as it appears in the `jps` output: e.g. `Computey`
+
+Alternatively, you may specify `-d` (duration) argument to profile
+the application for a fixed period of time with a single command.
+
+```
+$ ./profiler.sh -d 30 8983
+```
+
+By default, the profiling frequency is 100Hz (every 10ms of CPU time).
+Here is a sample of the output printed to the Java application's terminal:
+
+```
+--- Execution profile ---
+Total samples:           687
+Unknown (native):        1 (0.15%)
+
+--- 6790000000 (98.84%) ns, 679 samples
+  [ 0] Primes.isPrime
+  [ 1] Primes.primesThread
+  [ 2] Primes.access$000
+  [ 3] Primes$1.run
+  [ 4] java.lang.Thread.run
+
+... a lot of output omitted for brevity ...
+
+          ns  percent  samples  top
+  ----------  -------  -------  ---
+  6790000000   98.84%      679  Primes.isPrime
+    40000000    0.58%        4  __do_softirq
+
+... more output omitted ...
+```
+
+This indicates that the hottest method was `Primes.isPrime`, and the hottest
+call stack leading to it comes from `Primes.primesThread`.
+
+## Launching as an Agent
+
+If you need to profile some code as soon as the JVM starts up, instead of using the `profiler.sh` script,
+it is possible to attach async-profiler as an agent on the command line. For example:
+
+```
+$ java -agentpath:/path/to/libasyncProfiler.so=start,event=cpu,file=profile.html ...
+```
+
+Agent library is configured through the JVMTI argument interface.
+The format of the arguments string is described
+[in the source code](https://github.com/jvm-profiling-tools/async-profiler/blob/v2.9/src/arguments.cpp#L52).
+The `profiler.sh` script actually converts command line arguments to that format.
+
+For instance, `-e wall` is converted to `event=wall`, `-f profile.html`
+is converted to `file=profile.html`, and so on. However, some arguments are processed
+directly by `profiler.sh` script. E.g. `-d 5` results in 3 actions:
+attaching profiler agent with start command, sleeping for 5 seconds,
+and then attaching the agent again with stop command.
+
+## Multiple events
+
+It is possible to profile CPU, allocations, and locks at the same time.
+Or, instead of CPU, you may choose any other execution event: wall-clock,
+perf event, tracepoint, Java method, etc.
+
+The only output format that supports multiple events together is JFR.
+The recording will contain the following event types:
+ - `jdk.ExecutionSample`
+ - `jdk.ObjectAllocationInNewTLAB` (alloc)
+ - `jdk.ObjectAllocationOutsideTLAB` (alloc)
+ - `jdk.JavaMonitorEnter` (lock)
+ - `jdk.ThreadPark` (lock)
+
+To start profiling cpu + allocations + locks together, specify
+```
+./profiler.sh -e cpu,alloc,lock -f profile.jfr ...
+```
+or use `--alloc` and `--lock` parameters with the desired threshold:
+```
+./profiler.sh -e cpu --alloc 2m --lock 10ms -f profile.jfr ...
+```
+The same, when starting profiler as an agent:
+```
+-agentpath:/path/to/libasyncProfiler.so=start,event=cpu,alloc=2m,lock=10ms,file=profile.jfr
+```
+
+## Flame Graph visualization
+
+async-profiler provides out-of-the-box [Flame Graph](https://github.com/BrendanGregg/FlameGraph) support.
+Specify `-o flamegraph` argument to dump profiling results as an interactive HTML Flame Graph.
+Also, Flame Graph output format will be chosen automatically if the target filename ends with `.html`.
+
+```
+$ jps
+9234 Jps
+8983 Computey
+$ ./profiler.sh -d 30 -f /tmp/flamegraph.html 8983
+```
+
+[![Example](https://github.com/jvm-profiling-tools/async-profiler/blob/master/demo/flamegraph.png)](https://htmlpreview.github.io/?https://github.com/jvm-profiling-tools/async-profiler/blob/master/demo/flamegraph.html)
+
+## Profiler Options
+
+The following is a complete list of the command-line options accepted by
+`profiler.sh` script.
+
+* `start` - starts profiling in semi-automatic mode, i.e. profiler will run
+  until `stop` command is explicitly called.
+
+* `resume` - starts or resumes earlier profiling session that has been stopped.
+  All the collected data remains valid. The profiling options are not preserved
+  between sessions, and should be specified again.
+
+* `stop` - stops profiling and prints the report.
+
+* `dump` - dump collected data without stopping profiling session.
+
+* `check` - check if the specified profiling event is available.
+
+* `status` - prints profiling status: whether profiler is active and
+  for how long.
+
+* `meminfo` - prints used memory statistics.
+
+* `list` - show the list of profiling events available for the target process
+  (if PID is specified) or for the default JVM.
+
+* `-d N` - the profiling duration, in seconds. If no `start`, `resume`, `stop`
+  or `status` option is given, the profiler will run for the specified period
+  of time and then automatically stop.  
+  Example: `./profiler.sh -d 30 8983`
+
+* `-e event` - the profiling event: `cpu`, `alloc`, `lock`, `cache-misses` etc.
+  Use `list` to see the complete list of available events.
+
+  In allocation profiling mode the top frame of every call trace is the class
+  of the allocated object, and the counter is the heap pressure (the total size
+  of allocated TLABs or objects outside TLAB).
+
+  In lock profiling mode the top frame is the class of lock/monitor, and
+  the counter is number of nanoseconds it took to enter this lock/monitor.
+
+  Two special event types are supported on Linux: hardware breakpoints
+  and kernel tracepoints:
+    - `-e mem:<func>[:rwx]` sets read/write/exec breakpoint at function
+      `<func>`. The format of `mem` event is the same as in `perf-record`.
+      Execution breakpoints can be also specified by the function name,
+      e.g. `-e malloc` will trace all calls of native `malloc` function.
+    - `-e trace:<id>` sets a kernel tracepoint. It is possible to specify
+      tracepoint symbolic name, e.g. `-e syscalls:sys_enter_open` will trace
+      all `open` syscalls.
+
+* `-i N` - sets the profiling interval in nanoseconds or in other units,
+  if N is followed by `ms` (for milliseconds), `us` (for microseconds),
+  or `s` (for seconds). Only CPU active time is counted. No samples
+  are collected while CPU is idle. The default is 10000000 (10ms).  
+  Example: `./profiler.sh -i 500us 8983`
+
+* `--alloc N` - allocation profiling interval in bytes or in other units,
+  if N is followed by `k` (kilobytes), `m` (megabytes), or `g` (gigabytes).
+
+* `--live` - retain allocation samples with live objects only
+  (object that have not been collected by the end of profiling session).
+  Useful for finding Java heap memory leaks.
+
+* `--lock N` - lock profiling threshold in nanoseconds (or other units).
+  In lock profiling mode, record contended locks that the JVM has waited for
+  longer than the specified duration.
+
+* `-j N` - sets the Java stack profiling depth. This option will be ignored if N is greater
+  than default 2048.  
+  Example: `./profiler.sh -j 30 8983`
+
+* `-t` - profile threads separately. Each stack trace will end with a frame
+  that denotes a single thread.  
+  Example: `./profiler.sh -t 8983`
+
+* `-s` - print simple class names instead of FQN.
+
+* `-g` - print method signatures.
+
+* `-a` - annotate JIT compiled methods with `_[j]`, inlined methods with `_[i]`, interpreted methods with `_[0]` and C1 compiled methods with `_[1]`.
+
+* `-l` - prepend library names to symbols, e.g. ``libjvm.so`JVM_DefineClassWithSource``.
+
+* `-o fmt` - specifies what information to dump when profiling ends.
+  `fmt` can be one of the following options:
+    - `traces[=N]` - dump call traces (at most N samples);
+    - `flat[=N]` - dump flat profile (top N hot methods);  
+      can be combined with `traces`, e.g. `traces=200,flat=200`
+    - `jfr` - dump events in Java Flight Recorder format readable by Java Mission Control.
+      This *does not* require JDK commercial features to be enabled.
+    - `collapsed` - dump collapsed call traces in the format used by
+      [FlameGraph](https://github.com/brendangregg/FlameGraph) script. This is
+      a collection of call stacks, where each line is a semicolon separated list
+      of frames followed by a counter.
+    - `flamegraph` - produce Flame Graph in HTML format.
+    - `tree` - produce Call Tree in HTML format.  
+      `--reverse` option will generate backtrace view.
+
+* `--total` - count the total value of the collected metric instead of the number of samples,
+  e.g. total allocation size.
+
+* `--chunksize N`, `--chunktime N` - approximate size and time limits for a single JFR chunk.
+  Example: `./profiler.sh -f profile.jfr --chunksize 100m --chunktime 1h 8983`
+
+* `-I include`, `-X exclude` - filter stack traces by the given pattern(s).
+  `-I` defines the name pattern that *must* be present in the stack traces,
+  while `-X` is the pattern that *must not* occur in any of stack traces in the output.
+  `-I` and `-X` options can be specified multiple times. A pattern may begin or end with
+  a star `*` that denotes any (possibly empty) sequence of characters.  
+  Example: `./profiler.sh -I 'Primes.*' -I 'java/*' -X '*Unsafe.park*' 8983`
+
+* `--title TITLE`, `--minwidth PERCENT`, `--reverse` - FlameGraph parameters.  
+  Example: `./profiler.sh -f profile.html --title "Sample CPU profile" --minwidth 0.5 8983`
+
+* `-f FILENAME` - the file name to dump the profile information to.  
+  `%p` in the file name is expanded to the PID of the target JVM;  
+  `%t` - to the timestamp;  
+  `%n{MAX}` - to the sequence number;  
+  `%{ENV}` - to the value of the given environment variable.  
+  Example: `./profiler.sh -o collapsed -f /tmp/traces-%t.txt 8983`
+
+* `--loop TIME` - run profiler in a loop (continuous profiling).
+  The argument is either a clock time (`hh:mm:ss`) or
+  a loop duration in `s`econds, `m`inutes, `h`ours, or `d`ays.
+  Make sure the filename includes a timestamp pattern, or the output
+  will be overwritten on each iteration.  
+  Example: `./profiler.sh --loop 1h -f /var/log/profile-%t.jfr 8983`
+
+* `--all-user` - include only user-mode events. This option is helpful when kernel profiling
+  is restricted by `perf_event_paranoid` settings.  
+
+* `--sched` - group threads by Linux-specific scheduling policy: BATCH/IDLE/OTHER.
+
+* `--cstack MODE` - how to walk native frames (C stack). Possible modes are
+  `fp` (Frame Pointer), `dwarf` (DWARF unwind info),
+  `lbr` (Last Branch Record, available on Haswell since Linux 4.1),
+  and `no` (do not collect C stack).
+
+  By default, C stack is shown in cpu, itimer, wall-clock and perf-events profiles.
+  Java-level events like `alloc` and `lock` collect only Java stack.
+
+* `--begin function`, `--end function` - automatically start/stop profiling
+  when the specified native function is executed.
+
+* `--ttsp` - time-to-safepoint profiling. An alias for  
+  `--begin SafepointSynchronize::begin --end RuntimeService::record_safepoint_synchronized`  
+  It is not a separate event type, but rather a constraint. Whatever event type
+  you choose (e.g. `cpu` or `wall`), the profiler will work as usual, except that
+  only events between the safepoint request and the start of the VM operation
+  will be recorded.
+
+* `--jfrsync CONFIG` - start Java Flight Recording with the given configuration
+  synchronously with the profiler. The output .jfr file will include all regular
+  JFR events, except that execution samples will be obtained from async-profiler.
+  This option implies `-o jfr`.
+    - `CONFIG` is a predefined JFR profile or a JFR configuration file (.jfc).
+
+  Example: `./profiler.sh -e cpu --jfrsync profile -f combined.jfr 8983`
+
+* `--fdtransfer` - runs "fdtransfer" alongside, which is a small program providing an interface
+  for the profiler to access `perf_event_open` even while this syscall is unavailable for the
+  profiled process (due to low privileges).
+  See [Profiling Java in a container](#profiling-java-in-a-container).
+
+* `-v`, `--version` - prints the version of profiler library. If PID is specified,
+  gets the version of the library loaded into the given process.
+
+## Profiling Java in a container
+
+It is possible to profile Java processes running in a Docker or LXC container
+both from within a container and from the host system.
+
+When profiling from the host, `pid` should be the Java process ID in the host
+namespace. Use `ps aux | grep java` or `docker top <container>` to find
+the process ID.
+
+async-profiler should be run from the host by a privileged user - it will
+automatically switch to the proper pid/mount namespace and change
+user credentials to match the target process. Also make sure that
+the target container can access `libasyncProfiler.so` by the same
+absolute path as on the host.
+
+By default, Docker container restricts the access to `perf_event_open`
+syscall. There are 3 alternatives to allow profiling in a container:
+1. You can modify the [seccomp profile](https://docs.docker.com/engine/security/seccomp/)
+or disable it altogether with `--security-opt seccomp=unconfined` option. In
+addition, `--cap-add SYS_ADMIN` may be required.
+2. You can use "fdtransfer": see the help for `--fdtransfer`.
+3. Last, you may fall back to `-e itimer` profiling mode, see [Troubleshooting](#troubleshooting).
+
+## Restrictions/Limitations
+
+* macOS profiling is limited to user space code only.
+
+* On most Linux systems, `perf_events` captures call stacks with a maximum depth
+  of 127 frames. On recent Linux kernels, this can be configured using
+  `sysctl kernel.perf_event_max_stack` or by writing to the
+  `/proc/sys/kernel/perf_event_max_stack` file.
+
+* Profiler allocates 8kB perf_event buffer for each thread of the target process.
+  Make sure `/proc/sys/kernel/perf_event_mlock_kb` value is large enough
+  (more than `8 * threads`) when running under unprivileged user.
+  Otherwise the message _"perf_event mmap failed: Operation not permitted"_
+  will be printed, and no native stack traces will be collected.
+
+* There is no bullet-proof guarantee that the `perf_events` overflow signal
+  is delivered to the Java thread in a way that guarantees no other code has run,
+  which means that in some rare cases, the captured Java stack might not match
+  the captured native (user+kernel) stack.
+
+* You will not see the non-Java frames _preceding_ the Java frames on the
+  stack. For example, if `start_thread` called `JavaMain` and then your Java
+  code started running, you will not see the first two frames in the resulting
+  stack. On the other hand, you _will_ see non-Java frames (user and kernel)
+  invoked by your Java code.
+
+* No Java stacks will be collected if `-XX:MaxJavaStackTraceDepth` is zero
+  or negative.
+
+* Too short profiling interval may cause continuous interruption of heavy
+  system calls like `clone()`, so that it will never complete;
+  see [#97](https://github.com/jvm-profiling-tools/async-profiler/issues/97).
+  The workaround is simply to increase the interval.
+
+* When agent is not loaded at JVM startup (by using -agentpath option) it is
+  highly recommended to use `-XX:+UnlockDiagnosticVMOptions -XX:+DebugNonSafepoints` JVM flags.
+  Without those flags the profiler will still work correctly but results might be
+  less accurate. For example, without `-XX:+DebugNonSafepoints` there is a high chance
+  that simple inlined methods will not appear in the profile. When the agent is attached at runtime,
+  `CompiledMethodLoad` JVMTI event enables debug info, but only for methods compiled after attaching.
+
+## Troubleshooting
+
+```
+Failed to change credentials to match the target process: Operation not permitted
+```
+Due to limitation of HotSpot Dynamic Attach mechanism, the profiler must be run
+by exactly the same user (and group) as the owner of target JVM process.
+If profiler is run by a different user, it will try to automatically change
+current user and group. This will likely succeed for `root`, but not for
+other users, resulting in the above error.
+
+```
+Could not start attach mechanism: No such file or directory
+```
+The profiler cannot establish communication with the target JVM through UNIX domain socket.
+
+Usually this happens in one of the following cases:
+1. Attach socket `/tmp/.java_pidNNN` has been deleted. It is a common
+   practice to clean `/tmp` automatically with some scheduled script.
+   Configure the cleanup software to exclude `.java_pid*` files from deletion.  
+   How to check: run `lsof -p PID | grep java_pid`  
+   If it lists a socket file, but the file does not exist, then this is exactly
+   the described problem.
+2. JVM is started with `-XX:+DisableAttachMechanism` option.
+3. `/tmp` directory of Java process is not physically the same directory
+   as `/tmp` of your shell, because Java is running in a container or in
+   `chroot` environment. `jattach` attempts to solve this automatically,
+   but it might lack the required permissions to do so.  
+   Check `strace build/jattach PID properties`
+4. JVM is busy and cannot reach a safepoint. For instance,
+   JVM is in the middle of long-running garbage collection.  
+   How to check: run `kill -3 PID`. Healthy JVM process should print
+   a thread dump and heap info in its console.
+
+```
+Failed to inject profiler into <pid>
+```
+The connection with the target JVM has been established, but JVM is unable to load profiler shared library.
+Make sure the user of JVM process has permissions to access `libasyncProfiler.so` by exactly the same absolute path.
+For more information see [#78](https://github.com/jvm-profiling-tools/async-profiler/issues/78).
+
+```
+No access to perf events. Try --fdtransfer or --all-user option or 'sysctl kernel.perf_event_paranoid=1'
+```
+or
+```
+Perf events unavailable
+```
+`perf_event_open()` syscall has failed.
+
+Typical reasons include:
+1. `/proc/sys/kernel/perf_event_paranoid` is set to restricted mode (>=2).
+2. seccomp disables `perf_event_open` API in a container.
+3. OS runs under a hypervisor that does not virtualize performance counters.
+4. perf_event_open API is not supported on this system, e.g. WSL.
+
+For permissions-related reasons (such as 1 and 2), using `--fdtransfer` while running the profiler
+as a privileged user will allow using perf_events.
+
+If changing the configuration is not possible, you may fall back to
+`-e itimer` profiling mode. It is similar to `cpu` mode, but does not
+require perf_events support. As a drawback, there will be no kernel
+stack traces.
+
+```
+No AllocTracer symbols found. Are JDK debug symbols installed?
+```
+The OpenJDK debug symbols are required for allocation profiling.
+See [Installing Debug Symbols](#installing-debug-symbols) for more details.
+If the error message persists after a successful installation of the debug symbols,
+it is possible that the JDK was upgraded when installing the debug symbols.
+In this case, profiling any Java process which had started prior to the installation
+will continue to display this message, since the process had loaded
+the older version of the JDK which lacked debug symbols.
+Restarting the affected Java processes should resolve the issue.
+
+```
+VMStructs unavailable. Unsupported JVM?
+```
+JVM shared library does not export `gHotSpotVMStructs*` symbols -
+apparently this is not a HotSpot JVM. Sometimes the same message
+can be also caused by an incorrectly built JDK
+(see [#218](https://github.com/jvm-profiling-tools/async-profiler/issues/218)).
+In these cases installing JDK debug symbols may solve the problem.
+
+```
+Could not parse symbols from <libname.so>
+```
+Async-profiler was unable to parse non-Java function names because of
+the corrupted contents in `/proc/[pid]/maps`. The problem is known to
+occur in a container when running Ubuntu with Linux kernel 5.x.
+This is the OS bug, see https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1843018.
+
+```
+Could not open output file
+```
+Output file is written by the target JVM process, not by the profiler script.
+Make sure the path specified in `-f` option is correct and is accessible by the JVM.

demo/flamegraph.html

@@ -0,0 +1,882 @@
+<!DOCTYPE html>
+<html lang='en'>
+<head>
+<meta charset='utf-8'>
+<style>
+	body {margin: 0; padding: 10px; background-color: #ffffff}
+	h1 {margin: 5px 0 0 0; font-size: 18px; font-weight: normal; text-align: center}
+	header {margin: -24px 0 5px 0; line-height: 24px}
+	button {font: 12px sans-serif; cursor: pointer}
+	p {margin: 5px 0 5px 0}
+	a {color: #0366d6}
+	#hl {position: absolute; display: none; overflow: hidden; white-space: nowrap; pointer-events: none; background-color: #ffffe0; outline: 1px solid #ffc000; height: 15px}
+	#hl span {padding: 0 3px 0 3px}
+	#status {overflow: hidden; white-space: nowrap}
+	#match {overflow: hidden; white-space: nowrap; display: none; float: right; text-align: right}
+	#reset {cursor: pointer}
+</style>
+</head>
+<body style='font: 12px Verdana, sans-serif'>
+<h1>Flame Graph</h1>
+<header style='text-align: left'><button id='reverse' title='Reverse'>&#x1f53b;</button>&nbsp;&nbsp;<button id='search' title='Search'>&#x1f50d;</button></header>
+<header style='text-align: right'>Produced by <a href='https://github.com/jvm-profiling-tools/async-profiler'>async-profiler</a></header>
+<canvas id='canvas' style='width: 100%; height: 752px'></canvas>
+<div id='hl'><span></span></div>
+<p id='match'>Matched: <span id='matchval'></span> <span id='reset' title='Clear'>&#x274c;</span></p>
+<p id='status'>&nbsp;</p>
+<script>
+	// Copyright 2020 Andrei Pangin
+	// Licensed under the Apache License, Version 2.0.
+	'use strict';
+	var root, rootLevel, px, pattern;
+	var reverse = false;
+	const levels = Array(47);
+	for (let h = 0; h < levels.length; h++) {
+		levels[h] = [];
+	}
+
+	const canvas = document.getElementById('canvas');
+	const c = canvas.getContext('2d');
+	const hl = document.getElementById('hl');
+	const status = document.getElementById('status');
+
+	const canvasWidth = canvas.offsetWidth;
+	const canvasHeight = canvas.offsetHeight;
+	canvas.style.width = canvasWidth + 'px';
+	canvas.width = canvasWidth * (devicePixelRatio || 1);
+	canvas.height = canvasHeight * (devicePixelRatio || 1);
+	if (devicePixelRatio) c.scale(devicePixelRatio, devicePixelRatio);
+	c.font = document.body.style.font;
+
+	const palette = [
+		[0x50e150, 30, 30, 30],
+		[0x50bebe, 30, 30, 30],
+		[0xe17d00, 30, 30,  0],
+		[0xc8c83c, 30, 30, 10],
+		[0xe15a5a, 30, 40, 40],
+	];
+
+	function getColor(p) {
+		const v = Math.random();
+		return '#' + (p[0] + ((p[1] * v) << 16 | (p[2] * v) << 8 | (p[3] * v))).toString(16);
+	}
+
+	function f(level, left, width, type, title) {
+		levels[level].push({left: left, width: width, color: getColor(palette[type]), title: title});
+	}
+
+	function samples(n) {
+		return n === 1 ? '1 sample' : n.toString().replace(/\B(?=(\d{3})+(?!\d))/g, ',') + ' samples';
+	}
+
+	function pct(a, b) {
+		return a >= b ? '100' : (100 * a / b).toFixed(2);
+	}
+
+	function findFrame(frames, x) {
+		let left = 0;
+		let right = frames.length - 1;
+
+		while (left <= right) {
+			const mid = (left + right) >>> 1;
+			const f = frames[mid];
+
+			if (f.left > x) {
+				right = mid - 1;
+			} else if (f.left + f.width <= x) {
+				left = mid + 1;
+			} else {
+				return f;
+			}
+		}
+
+		if (frames[left] && (frames[left].left - x) * px < 0.5) return frames[left];
+		if (frames[right] && (x - (frames[right].left + frames[right].width)) * px < 0.5) return frames[right];
+
+		return null;
+	}
+
+	function search(r) {
+		if (r && (r = prompt('Enter regexp to search:', '')) === null) {
+			return;
+		}
+
+		pattern = r ? RegExp(r) : undefined;
+		const matched = render(root, rootLevel);
+		document.getElementById('matchval').textContent = pct(matched, root.width) + '%';
+		document.getElementById('match').style.display = r ? 'inherit' : 'none';
+	}
+
+	function render(newRoot, newLevel) {
+		if (root) {
+			c.fillStyle = '#ffffff';
+			c.fillRect(0, 0, canvasWidth, canvasHeight);
+		}
+
+		root = newRoot || levels[0][0];
+		rootLevel = newLevel || 0;
+		px = canvasWidth / root.width;
+
+		const x0 = root.left;
+		const x1 = x0 + root.width;
+		const marked = [];
+
+		function mark(f) {
+			return marked[f.left] >= f.width || (marked[f.left] = f.width);
+		}
+
+		function totalMarked() {
+			let total = 0;
+			let left = 0;
+			for (let x in marked) {
+				if (+x >= left) {
+					total += marked[x];
+					left = +x + marked[x];
+				}
+			}
+			return total;
+		}
+
+		function drawFrame(f, y, alpha) {
+			if (f.left < x1 && f.left + f.width > x0) {
+				c.fillStyle = pattern && f.title.match(pattern) && mark(f) ? '#ee00ee' : f.color;
+				c.fillRect((f.left - x0) * px, y, f.width * px, 15);
+
+				if (f.width * px >= 21) {
+					const chars = Math.floor(f.width * px / 7);
+					const title = f.title.length <= chars ? f.title : f.title.substring(0, chars - 2) + '..';
+					c.fillStyle = '#000000';
+					c.fillText(title, Math.max(f.left - x0, 0) * px + 3, y + 12, f.width * px - 6);
+				}
+
+				if (alpha) {
+					c.fillStyle = 'rgba(255, 255, 255, 0.5)';
+					c.fillRect((f.left - x0) * px, y, f.width * px, 15);
+				}
+			}
+		}
+
+		for (let h = 0; h < levels.length; h++) {
+			const y = reverse ? h * 16 : canvasHeight - (h + 1) * 16;
+			const frames = levels[h];
+			for (let i = 0; i < frames.length; i++) {
+				drawFrame(frames[i], y, h < rootLevel);
+			}
+		}
+
+		return totalMarked();
+	}
+
+	canvas.onmousemove = function() {
+		const h = Math.floor((reverse ? event.offsetY : (canvasHeight - event.offsetY)) / 16);
+		if (h >= 0 && h < levels.length) {
+			const f = findFrame(levels[h], event.offsetX / px + root.left);
+			if (f) {
+				if (f != root) getSelection().removeAllRanges();
+				hl.style.left = (Math.max(f.left - root.left, 0) * px + canvas.offsetLeft) + 'px';
+				hl.style.width = (Math.min(f.width, root.width) * px) + 'px';
+				hl.style.top = ((reverse ? h * 16 : canvasHeight - (h + 1) * 16) + canvas.offsetTop) + 'px';
+				hl.firstChild.textContent = f.title;
+				hl.style.display = 'block';
+				canvas.title = f.title + '\n(' + samples(f.width) + ', ' + pct(f.width, levels[0][0].width) + '%)';
+				canvas.style.cursor = 'pointer';
+				canvas.onclick = function() {
+					if (f != root) {
+						render(f, h);
+						canvas.onmousemove();
+					}
+				};
+				status.textContent = 'Function: ' + canvas.title;
+				return;
+			}
+		}
+		canvas.onmouseout();
+	}
+
+	canvas.onmouseout = function() {
+		hl.style.display = 'none';
+		status.textContent = '\xa0';
+		canvas.title = '';
+		canvas.style.cursor = '';
+		canvas.onclick = '';
+	}
+
+	canvas.ondblclick = function() {
+		getSelection().selectAllChildren(hl);
+	}
+
+	document.getElementById('reverse').onclick = function() {
+		reverse = !reverse;
+		render();
+	}
+
+	document.getElementById('search').onclick = function() {
+		search(true);
+	}
+
+	document.getElementById('reset').onclick = function() {
+		search(false);
+	}
+
+	window.onkeydown = function() {
+		if (event.ctrlKey && event.keyCode === 70) {
+			event.preventDefault();
+			search(true);
+		} else if (event.keyCode === 27) {
+			search(false);
+		}
+	}
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+f(19,272,29,0,'java/util/stream/AbstractPipeline.copyInto')
+f(20,272,29,0,'java/util/Spliterator$OfInt.forEachRemaining')
+f(21,272,29,0,'java/util/stream/Streams$RangeIntSpliterator.forEachRemaining')
+f(22,272,29,0,'java/util/stream/ForEachOps$ForEachOp$OfInt.accept')
+f(23,272,29,0,'demo/parallel/MandelbrotSetTask$$Lambda$99/105194951.accept')
+f(24,272,29,0,'demo/parallel/MandelbrotSetTask.lambda$call$19')
+f(25,273,28,0,'demo/parallel/MandelbrotSetTask.calcAntialiasedPixel')
+f(26,274,27,0,'demo/parallel/MandelbrotSetTask.calcPixel')
+f(27,274,27,0,'demo/parallel/MandelbrotSetTask.calc')
+f(28,287,3,0,'demo/parallel/Complex.lengthSQ')
+f(28,290,8,0,'demo/parallel/Complex.plus')
+f(28,298,3,0,'demo/parallel/Complex.times')
+f(7,301,107,0,'java/util/stream/Streams$RangeIntSpliterator.forEachRemaining')
+f(8,301,107,0,'demo/parallel/MandelbrotSetTask$$Lambda$99/105194951.accept')
+f(9,301,107,0,'demo/parallel/MandelbrotSetTask.lambda$call$19')
+f(10,301,105,0,'demo/parallel/MandelbrotSetTask.calcAntialiasedPixel')
+f(11,309,97,0,'demo/parallel/MandelbrotSetTask.calcPixel')
+f(12,312,94,0,'demo/parallel/MandelbrotSetTask.calc')
+f(13,357,23,0,'demo/parallel/Complex.lengthSQ')
+f(13,380,16,0,'demo/parallel/Complex.plus')
+f(13,396,10,0,'demo/parallel/Complex.times')
+f(6,408,5,0,'javafx/scene/image/WritableImage$2.setColor')
+f(7,408,3,0,'java/lang/Math.round')
+f(7,411,2,0,'javafx/scene/image/WritableImage$2.setArgb')
+f(8,411,2,0,'com/sun/prism/Image.setArgb')
+f(1,413,163,0,'java/util/concurrent/ForkJoinWorkerThread.run')
+f(2,413,163,0,'java/util/concurrent/ForkJoinPool.runWorker')
+f(3,413,163,0,'java/util/concurrent/ForkJoinPool$WorkQueue.runTask')
+f(4,413,38,0,'java/util/concurrent/ForkJoinPool$WorkQueue.execLocalTasks')
+f(5,413,38,0,'java/util/concurrent/ForkJoinTask.doExec')
+f(6,413,38,0,'java/util/concurrent/CountedCompleter.exec')
+f(7,413,38,0,'java/util/stream/ForEachOps$ForEachTask.compute')
+f(8,413,38,0,'java/util/stream/AbstractPipeline.copyInto')
+f(9,413,38,0,'java/util/Spliterator$OfInt.forEachRemaining')
+f(10,413,38,0,'java/util/stream/Streams$RangeIntSpliterator.forEachRemaining')
+f(11,413,38,0,'java/util/stream/ForEachOps$ForEachOp$OfInt.accept')
+f(12,413,38,0,'demo/parallel/MandelbrotSetTask$$Lambda$99/105194951.accept')
+f(13,413,38,0,'demo/parallel/MandelbrotSetTask.lambda$call$19')
+f(14,415,32,0,'demo/parallel/MandelbrotSetTask.calcAntialiasedPixel')
+f(15,421,26,0,'demo/parallel/MandelbrotSetTask.calcPixel')
+f(16,424,22,0,'demo/parallel/MandelbrotSetTask.calc')
+f(17,432,7,0,'demo/parallel/Complex.lengthSQ')
+f(17,439,7,0,'demo/parallel/Complex.plus')
+f(14,447,4,0,'javafx/scene/image/WritableImage$2.setColor')
+f(15,448,3,0,'javafx/scene/image/WritableImage$2.setArgb')
+f(16,449,2,0,'javafx/scene/image/Image.getWritablePlatformImage')
+f(4,451,125,0,'java/util/concurrent/ForkJoinTask.doExec')
+f(5,451,125,0,'java/util/concurrent/CountedCompleter.exec')
+f(6,451,125,0,'java/util/stream/ForEachOps$ForEachTask.compute')
+f(7,452,124,0,'java/util/stream/AbstractPipeline.copyInto')
+f(8,452,124,0,'java/util/Spliterator$OfInt.forEachRemaining')
+f(9,452,124,0,'java/util/stream/Streams$RangeIntSpliterator.forEachRemaining')
+f(10,452,124,0,'java/util/stream/ForEachOps$ForEachOp$OfInt.accept')
+f(11,452,124,0,'demo/parallel/MandelbrotSetTask$$Lambda$99/105194951.accept')
+f(12,452,124,0,'demo/parallel/MandelbrotSetTask.lambda$call$19')
+f(13,454,119,0,'demo/parallel/MandelbrotSetTask.calcAntialiasedPixel')
+f(14,462,111,0,'demo/parallel/MandelbrotSetTask.calcPixel')
+f(15,464,109,0,'demo/parallel/MandelbrotSetTask.calc')
+f(16,504,39,0,'demo/parallel/Complex.lengthSQ')
+f(16,543,22,0,'demo/parallel/Complex.plus')
+f(16,565,8,0,'demo/parallel/Complex.times')
+f(13,573,3,0,'javafx/scene/image/WritableImage$2.setColor')
+f(1,576,65,4,'start_thread')
+f(2,576,65,4,'java_start(Thread*)')
+f(3,576,4,3,'GCTaskThread::run()')
+f(4,577,3,3,'OldToYoungRootsTask::do_it(GCTaskManager*, unsigned int)')
+f(5,577,3,3,'CardTableExtension::scavenge_contents_parallel(ObjectStartArray*, MutableSpace*, HeapWord*, PSPromotionManager*, unsigned int, unsigned int)')
+f(6,577,3,3,'PSPromotionManager::drain_stacks_depth(bool)')
+f(7,578,2,3,'oopDesc* PSPromotionManager::copy_to_survivor_space<false>(oopDesc*)')
+f(3,580,61,3,'JavaThread::run()')
+f(4,580,61,3,'JavaThread::thread_main_inner()')
+f(5,580,61,3,'CompileBroker::compiler_thread_loop()')
+f(6,580,58,3,'CompileBroker::invoke_compiler_on_method(CompileTask*)')
+f(7,580,58,3,'C2Compiler::compile_method(ciEnv*, ciMethod*, int)')
+f(8,580,58,3,'Compile::Compile(ciEnv*, C2Compiler*, ciMethod*, int, bool, bool, bool)')
+f(9,580,32,3,'Compile::Code_Gen()')
+f(10,582,3,3,'PhaseCFG::do_global_code_motion()')
+f(11,582,3,3,'PhaseCFG::global_code_motion()')
+f(10,585,27,3,'PhaseChaitin::Register_Allocate()')
+f(11,585,2,3,'PhaseChaitin::Select()')
+f(12,585,2,3,'PhaseIFG::re_insert(unsigned int)')
+f(11,589,9,3,'PhaseChaitin::build_ifg_physical(ResourceArea*)')
+f(12,592,3,3,'PhaseChaitin::interfere_with_live(unsigned int, IndexSet*)')
+f(12,596,2,3,'RegMask::smear_to_sets(int)')
+f(11,599,3,3,'PhaseChaitin::gather_lrg_masks(bool)')
+f(11,602,5,3,'PhaseChaitin::post_allocate_copy_removal()')
+f(12,604,2,3,'PhaseChaitin::elide_copy(Node*, int, Block*, Node_List&, Node_List&, bool)')
+f(11,609,2,3,'PhaseIFG::init(unsigned int)')
+f(12,609,2,3,'IndexSet::initialize(unsigned int)')
+f(9,613,15,3,'Compile::Optimize()')
+f(10,614,13,3,'PhaseIdealLoop::build_and_optimize(bool, bool)')
+f(11,617,2,3,'PhaseIdealLoop::build_loop_early(VectorSet&, Node_List&, Node_Stack&)')
+f(11,619,4,3,'PhaseIdealLoop::build_loop_late(VectorSet&, Node_List&, Node_Stack&)')
+f(11,625,2,3,'PhaseIterGVN::optimize()')
+f(12,625,2,3,'PhaseIterGVN::transform_old(Node*)')
+f(9,629,3,3,'ParseGenerator::generate(JVMState*)')
+f(10,629,3,3,'Parse::Parse(JVMState*, ciMethod*, float)')
+f(11,629,3,3,'Parse::do_all_blocks()')
+f(12,629,3,3,'Parse::do_one_block()')
+f(13,629,3,3,'Parse::do_one_bytecode()')
+f(14,629,3,3,'Parse::do_call()')
+f(15,630,2,3,'PredictedCallGenerator::generate(JVMState*)')
+f(16,630,2,3,'ParseGenerator::generate(JVMState*)')
+f(17,630,2,3,'Parse::Parse(JVMState*, ciMethod*, float)')
+f(18,630,2,3,'Parse::do_all_blocks()')
+f(19,630,2,3,'Parse::do_one_block()')
+f(20,630,2,3,'Parse::do_one_bytecode()')
+f(21,630,2,3,'Parse::do_call()')
+f(9,632,6,3,'ciEnv::register_method(ciMethod*, int, CodeOffsets*, int, CodeBuffer*, int, OopMapSet*, ExceptionHandlerTable*, ImplicitExceptionTable*, AbstractCompiler*, int, bool, bool, RTMState)')
+f(10,632,6,3,'nmethod::post_compiled_method_load_event()')
+f(11,632,6,4,'pthread_cond_signal@@GLIBC_2.3.2')
+f(12,632,6,2,'entry_SYSCALL_64_after_hwframe')
+f(13,632,6,2,'do_syscall_64')
+f(14,632,6,2,'__x64_sys_futex')
+f(15,632,6,2,'do_futex')
+f(16,632,6,2,'wake_up_q')
+f(17,632,6,2,'try_to_wake_up')
+f(18,632,6,2,'_raw_spin_unlock_irqrestore')
+f(6,638,3,3,'CompileQueue::get()')
+f(7,638,3,4,'pthread_cond_signal@@GLIBC_2.3.2')
+f(8,638,3,2,'entry_SYSCALL_64_after_hwframe')
+f(9,638,3,2,'do_syscall_64')
+f(10,638,3,2,'__x64_sys_futex')
+f(11,638,3,2,'do_futex')
+f(12,638,3,2,'wake_up_q')
+f(13,638,3,2,'try_to_wake_up')
+f(14,638,3,2,'_raw_spin_unlock_irqrestore')
+render();
+</script></body></html>

pom-converter.xml

@@ -0,0 +1,119 @@
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <groupId>tools.profiler</groupId>
+    <artifactId>async-profiler-converter</artifactId>
+    <version>2.9</version>
+    <packaging>jar</packaging>
+
+    <name>async-profiler</name>
+    <url>https://profiler.tools</url>
+    <description>Low overhead sampling profiler for Java</description>
+
+    <licenses>
+        <license>
+            <name>Apache License Version 2.0</name>
+            <url>http://www.apache.org/licenses/LICENSE-2.0</url>
+            <distribution>repo</distribution>
+        </license>
+    </licenses>
+    <scm>
+        <url>https://github.com/jvm-profiling-tools/async-profiler</url>
+        <connection>scm:git:git@github.com:jvm-profiling-tools/async-profiler.git</connection>
+        <developerConnection>scm:git:git@github.com:jvm-profiling-tools/async-profiler.git</developerConnection>
+    </scm>
+    <developers>
+        <developer>
+            <id>apangin</id>
+            <name>Andrei Pangin</name>
+            <email>noreply@pangin.pro</email>
+        </developer>
+    </developers>
+
+    <properties>
+        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+    </properties>
+
+    <build>
+        <sourceDirectory>src/converter</sourceDirectory>
+        <resources>
+            <resource>
+                <directory>src/res</directory>
+            </resource>
+        </resources>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <version>3.8.1</version>
+                <configuration>
+                    <source>7</source>
+                    <target>7</target>
+                </configuration>
+            </plugin>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-jar-plugin</artifactId>
+                <version>3.3.0</version>
+                <configuration>
+                    <archive>
+                        <manifest>
+                            <mainClass>Main</mainClass>
+                        </manifest>
+                    </archive>
+                </configuration>
+            </plugin>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-source-plugin</artifactId>
+                <version>3.2.0</version>
+                <executions>
+                    <execution>
+                        <id>attach-sources</id>
+                        <goals>
+                            <goal>jar-no-fork</goal>
+                        </goals>
+                    </execution>
+                </executions>
+            </plugin>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-javadoc-plugin</artifactId>
+                <version>3.2.0</version>
+                <executions>
+                    <execution>
+                        <id>attach-javadocs</id>
+                        <goals>
+                            <goal>jar</goal>
+                        </goals>
+                    </execution>
+                </executions>
+            </plugin>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-gpg-plugin</artifactId>
+                <version>1.6</version>
+                <executions>
+                    <execution>
+                        <id>sign-artifacts</id>
+                        <phase>verify</phase>
+                        <goals>
+                            <goal>sign</goal>
+                        </goals>
+                    </execution>
+                </executions>
+            </plugin>
+        </plugins>
+    </build>
+
+    <distributionManagement>
+        <snapshotRepository>
+            <id>ossrh</id>
+            <url>https://oss.sonatype.org/content/repositories/snapshots</url>
+        </snapshotRepository>
+        <repository>
+            <id>ossrh</id>
+            <url>https://oss.sonatype.org/service/local/staging/deploy/maven2</url>
+        </repository>
+    </distributionManagement>
+</project>

pom.xml

@@ -3,7 +3,7 @@
     <modelVersion>4.0.0</modelVersion>
     <groupId>tools.profiler</groupId>
     <artifactId>async-profiler</artifactId>
-    <version>1.8.3</version>
+    <version>2.9</version>
     <packaging>jar</packaging>
 
     <name>async-profiler</name>
@@ -36,20 +36,51 @@
 
     <build>
         <sourceDirectory>src/api</sourceDirectory>
+        <resources>
+            <resource>
+                <directory>native</directory>
+            </resource>
+        </resources>
         <plugins>
             <plugin>
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-compiler-plugin</artifactId>
                 <version>3.8.1</version>
                 <configuration>
-                    <source>1.6</source>
-                    <target>1.6</target>
+                    <source>7</source>
+                    <target>7</target>
                 </configuration>
             </plugin>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-jar-plugin</artifactId>
+                <version>3.3.0</version>
+                <executions>
+                    <execution>
+                        <phase>package</phase>
+                        <goals>
+                            <goal>jar</goal>
+                        </goals>
+                        <configuration>
+                            <classifier>${native.platform}</classifier>
+                            <includes>
+                                <include>${native.platform}/*</include>
+                                <include>one/**</include>
+                            </includes>
+                        </configuration>
+                    </execution>
+                </executions>
+            </plugin>
             <plugin>
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-source-plugin</artifactId>
                 <version>3.2.0</version>
+                <configuration>
+                    <excludes>
+                        <exclude>linux*/**</exclude>
+                        <exclude>macos*/**</exclude>
+                    </excludes>
+                </configuration>
                 <executions>
                     <execution>
                         <id>attach-sources</id>

profiler.sh

@@ -7,9 +7,10 @@ usage() {
     echo "  start             start profiling and return immediately"
     echo "  resume            resume profiling without resetting collected data"
     echo "  stop              stop profiling"
-    echo "  jstack            get a thread dump"
+    echo "  dump              dump collected data without stopping profiling session"
     echo "  check             check if the specified profiling event is available"
     echo "  status            print profiling status"
+    echo "  meminfo           print profiler memory stats"
     echo "  list              list profiling events supported by the target JVM"
     echo "  collect           collect profile for the specified period of time"
     echo "                    and then stop (default action)"
@@ -22,8 +23,9 @@ usage() {
     echo "  -t                profile different threads separately"
     echo "  -s                simple class names instead of FQN"
     echo "  -g                print method signatures"
-    echo "  -a                annotate Java method names"
-    echo "  -o fmt            output format: flat|collapsed|html|tree|jfr"
+    echo "  -a                annotate Java methods"
+    echo "  -l                prepend library names"
+    echo "  -o fmt            output format: flat|traces|collapsed|flamegraph|tree|jfr"
     echo "  -I include        output only stack traces containing the specified pattern"
     echo "  -X exclude        exclude stack traces with the specified pattern"
     echo "  -v, --version     display version string"
@@ -32,17 +34,27 @@ usage() {
     echo "  --minwidth pct    skip frames smaller than pct%"
     echo "  --reverse         generate stack-reversed FlameGraph / Call tree"
     echo ""
-    echo "  --all-kernel      only include kernel-mode events"
+    echo "  --loop time       run profiler in a loop"
+    echo "  --alloc bytes     allocation profiling interval in bytes"
+    echo "  --live            build allocation profile from live objects only"
+    echo "  --lock duration   lock profiling threshold in nanoseconds"
+    echo "  --total           accumulate the total value (time, bytes, etc.)"
     echo "  --all-user        only include user-mode events"
-    echo "  --cstack mode     how to traverse C stack: fp|lbr|no"
+    echo "  --sched           group threads by scheduling policy"
+    echo "  --cstack mode     how to traverse C stack: fp|dwarf|lbr|no"
     echo "  --begin function  begin profiling when function is executed"
     echo "  --end function    end profiling when function is executed"
+    echo "  --ttsp            time-to-safepoint profiling"
+    echo "  --jfrsync config  synchronize profiler with JFR recording"
+    echo "  --lib path        full path to libasyncProfiler.so in the container"
+    echo "  --fdtransfer      use fdtransfer to serve perf requests"
+    echo "                    from the non-privileged target"
     echo ""
     echo "<pid> is a numeric process ID of the target JVM"
     echo "      or 'jps' keyword to find running JVM automatically"
     echo "      or the application's name as it would appear in the jps tool"
     echo ""
-    echo "Example: $0 -d 30 -f profile.svg 3456"
+    echo "Example: $0 -d 30 -f profile.html 3456"
     echo "         $0 start -i 999000 jps"
     echo "         $0 stop -o flat jps"
     echo "         $0 -d 5 -e alloc MyAppName"
@@ -55,10 +67,25 @@ mirror_output() {
         if [ -f "$FILE" ]; then
             cat "$FILE"
             rm "$FILE"
+        elif [ -f "$ROOT_PREFIX$FILE" ]; then
+            cat "$ROOT_PREFIX$FILE"
+            rm "$ROOT_PREFIX$FILE"
         fi
     fi
 }
 
+mirror_log() {
+    # Try to access the log file both directly and through /proc/[pid]/root,
+    # in case the target namespace differs
+    if [ -f "$LOG" ]; then
+        cat "$LOG" >&2
+        rm "$LOG"
+    elif [ -f "$ROOT_PREFIX$LOG" ]; then
+        cat "$ROOT_PREFIX$LOG" >&2
+        rm "$ROOT_PREFIX$LOG"
+    fi
+}
+
 check_if_terminated() {
     if ! kill -0 "$PID" 2> /dev/null; then
         mirror_output
@@ -66,34 +93,51 @@ check_if_terminated() {
     fi
 }
 
+fdtransfer() {
+    if [ "$USE_FDTRANSFER" = "true" ]; then
+        FDTRANSFER_PATH="@async-profiler-$(od -An -N3 -i /dev/random | xargs)"
+        PARAMS="$PARAMS,fdtransfer=$FDTRANSFER_PATH"
+        "$FDTRANSFER" "$FDTRANSFER_PATH" "$PID"
+    fi
+}
+
 jattach() {
     set +e
-    "$JATTACH" "$PID" load "$PROFILER" true "$1" > /dev/null
+    "$JATTACH" "$PID" load "$PROFILER" true "$1,log=$LOG" > /dev/null
     RET=$?
-    set -e
 
     # Check if jattach failed
     if [ $RET -ne 0 ]; then
         if [ $RET -eq 255 ]; then
             echo "Failed to inject profiler into $PID"
-            if [ "$(uname -s)" = "Darwin" ]; then
+            if [ "$UNAME_S" = "Darwin" ]; then
                 otool -L "$PROFILER"
             else
-                ldd "$PROFILER"
+                LD_PRELOAD="$PROFILER" /bin/true
             fi
         fi
+
+        mirror_log
         exit $RET
     fi
 
+    mirror_log
     mirror_output
+    set -e
 }
 
-OPTIND=1
-SCRIPT_DIR="$(cd "$(dirname "$0")" > /dev/null 2>&1; pwd -P)"
+SCRIPT_BIN="$0"
+while [ -h "$SCRIPT_BIN" ]; do
+    SCRIPT_BIN="$(readlink "$SCRIPT_BIN")"
+done
+SCRIPT_DIR="$(cd "$(dirname "$SCRIPT_BIN")" > /dev/null 2>&1; pwd -P)"
+
 JATTACH=$SCRIPT_DIR/build/jattach
+FDTRANSFER=$SCRIPT_DIR/build/fdtransfer
+USE_FDTRANSFER="false"
+FDTRANSFER_PATH=""
 PROFILER=$SCRIPT_DIR/build/libasyncProfiler.so
 ACTION="collect"
-EVENT="cpu"
 DURATION="60"
 FILE=""
 USE_TMP="true"
@@ -107,19 +151,14 @@ while [ $# -gt 0 ]; do
         -h|"-?")
             usage
             ;;
-        start|resume|stop|check|status|list|collect)
+        start|resume|stop|dump|check|status|meminfo|list|collect)
             ACTION="$1"
             ;;
-        jstack)
-            ACTION="start"
-            EVENT="jstack"
-            PARAMS="$PARAMS,threads"
-            ;;
         -v|--version)
             ACTION="version"
             ;;
         -e)
-            EVENT="$(echo "$2" | sed 's/,/,event=/g')"
+            PARAMS="$PARAMS,event=$2"
             shift
             ;;
         -d)
@@ -151,6 +190,9 @@ while [ $# -gt 0 ]; do
         -a)
             FORMAT="$FORMAT,ann"
             ;;
+        -l)
+            FORMAT="$FORMAT,lib"
+            ;;
         -o)
             OUTPUT="$2"
             shift
@@ -181,12 +223,29 @@ while [ $# -gt 0 ]; do
         --reverse)
             FORMAT="$FORMAT,reverse"
             ;;
-        --all-kernel)
-            PARAMS="$PARAMS,allkernel"
+        --samples|--total)
+            FORMAT="$FORMAT,${1#--}"
+            ;;
+        --alloc|--lock|--chunksize|--chunktime)
+            PARAMS="$PARAMS,${1#--}=$2"
+            shift
+            ;;
+        --timeout|--loop)
+            if [ "$ACTION" = "collect" ]; then
+                ACTION="start"
+            fi
+            PARAMS="$PARAMS,${1#--}=$2"
+            shift
             ;;
         --all-user)
             PARAMS="$PARAMS,alluser"
             ;;
+        --sched)
+            PARAMS="$PARAMS,sched"
+            ;;
+        --live)
+            PARAMS="$PARAMS,live"
+            ;;
         --cstack|--call-graph)
             PARAMS="$PARAMS,cstack=$2"
             shift
@@ -195,6 +254,21 @@ while [ $# -gt 0 ]; do
             PARAMS="$PARAMS,${1#--}=$2"
             shift
             ;;
+        --ttsp)
+            PARAMS="$PARAMS,begin=SafepointSynchronize::begin,end=RuntimeService::record_safepoint_synchronized"
+            ;;
+        --jfrsync)
+            OUTPUT="jfr"
+            PARAMS="$PARAMS,jfrsync=$2"
+            shift
+            ;;
+        --lib)
+            PROFILER="$2"
+            shift
+            ;;
+        --fdtransfer)
+            USE_FDTRANSFER="true"
+            ;;
         --safe-mode)
             PARAMS="$PARAMS,safemode=$2"
             shift
@@ -230,8 +304,19 @@ while [ $# -gt 0 ]; do
     shift
 done
 
-if [ "$PID" = "" ] && [ "$ACTION" != "version" ]; then
-    usage
+if [ "$PID" = "" ]; then
+    case "$ACTION" in
+        version)
+            java "-agentpath:$PROFILER=version=full" -version 2> /dev/null
+            ;;
+        list)
+            java "-agentpath:$PROFILER=list" -version 2> /dev/null
+            ;;
+        *)
+            usage
+            ;;
+    esac
+    exit 0
 fi
 
 # If no -f argument is given, use temporary file to transfer output to caller terminal.
@@ -249,34 +334,48 @@ else
             ;;
     esac
 fi
+LOG=/tmp/async-profiler-log.$$.$PID
+
+UNAME_S=$(uname -s)
+if [ "$UNAME_S" = "Linux" ]; then
+    ROOT_PREFIX="/proc/$PID/root"
+else
+    ROOT_PREFIX=""
+fi
 
 case $ACTION in
-    start|resume|check)
-        jattach "$ACTION,event=$EVENT,file=$FILE,$OUTPUT$FORMAT$PARAMS"
+    start|resume)
+        fdtransfer
+        jattach "$ACTION,file=$FILE,$OUTPUT$FORMAT$PARAMS"
         ;;
-    stop)
-        jattach "stop,file=$FILE,$OUTPUT$FORMAT"
+    check)
+        jattach "$ACTION,file=$FILE,$OUTPUT$FORMAT$PARAMS"
         ;;
-    status)
-        jattach "status,file=$FILE"
+    stop|dump)
+        jattach "$ACTION,file=$FILE,$OUTPUT$FORMAT"
         ;;
-    list)
-        jattach "list,file=$FILE"
+    status|meminfo|list)
+        jattach "$ACTION,file=$FILE"
+        ;;
+    version)
+        jattach "version=full,file=$FILE"
         ;;
     collect)
-        jattach "start,event=$EVENT,file=$FILE,$OUTPUT$FORMAT$PARAMS"
+        fdtransfer
+        jattach "start,file=$FILE,$OUTPUT$FORMAT$PARAMS"
+        echo Profiling for "$DURATION" seconds >&2
+        set +e
+        trap 'DURATION=0' INT
+
         while [ "$DURATION" -gt 0 ]; do
             DURATION=$(( DURATION-1 ))
             check_if_terminated
             sleep 1
         done
+
+        set -e
+        trap - INT
+        echo Done >&2
         jattach "stop,file=$FILE,$OUTPUT$FORMAT"
         ;;
-    version)
-        if [ "$PID" = "" ]; then
-            java "-agentpath:$PROFILER=version=full" -version 2> /dev/null
-        else
-            jattach "version=full,file=$FILE"
-        fi
-        ;;
 esac

src/allocTracer.cpp

@@ -15,22 +15,22 @@
  */
 
 #include "allocTracer.h"
-#include "os.h"
 #include "profiler.h"
 #include "stackFrame.h"
 #include "vmStructs.h"
 
 
 int AllocTracer::_trap_kind;
-Trap AllocTracer::_in_new_tlab;
-Trap AllocTracer::_outside_tlab;
+Trap AllocTracer::_in_new_tlab(0);
+Trap AllocTracer::_outside_tlab(1);
+volatile bool AllocTracer::_use_hook = false;
 
 u64 AllocTracer::_interval;
 volatile u64 AllocTracer::_allocated_bytes;
 
 
 // Called whenever our breakpoint trap is hit
-void AllocTracer::signalHandler(int signo, siginfo_t* siginfo, void* ucontext) {
+void AllocTracer::trapHandler(int signo, siginfo_t* siginfo, void* ucontext) {
     StackFrame frame(ucontext);
     int event_type;
     uintptr_t total_size;
@@ -51,6 +51,7 @@ void AllocTracer::signalHandler(int signo, siginfo_t* siginfo, void* ucontext) {
         instance_size = 0;
     } else {
         // Not our trap
+        Profiler::instance()->trapHandler(signo, siginfo, ucontext);
         return;
     }
 
@@ -58,31 +59,37 @@ void AllocTracer::signalHandler(int signo, siginfo_t* siginfo, void* ucontext) {
     uintptr_t klass = frame.arg0();
     frame.ret();
 
-    if (_enabled) {
-        // TODO: _enabled also uses traps
+    if (_enabled && updateCounter(_allocated_bytes, total_size, _interval)) {
         recordAllocation(ucontext, event_type, klass, total_size, instance_size);
     }
 }
 
+void AllocTracer::inNewTLAB1(uintptr_t klass, void* obj, size_t tlab_size, size_t alloc_size) {
+    if (_use_hook && _enabled && updateCounter(_allocated_bytes, tlab_size, _interval)) {
+        recordAllocation(NULL, BCI_ALLOC, klass, tlab_size, alloc_size);
+    }
+}
+
+void AllocTracer::outsideTLAB1(uintptr_t klass, void* obj, size_t alloc_size) {
+    if (_use_hook && _enabled && updateCounter(_allocated_bytes, alloc_size, _interval)) {
+        recordAllocation(NULL, BCI_ALLOC_OUTSIDE_TLAB, klass, alloc_size, 0);
+    }
+}
+
+void AllocTracer::inNewTLAB2(uintptr_t klass, size_t tlab_size, size_t alloc_size) {
+    if (_use_hook && _enabled && updateCounter(_allocated_bytes, tlab_size, _interval)) {
+        recordAllocation(NULL, BCI_ALLOC, klass, tlab_size, alloc_size);
+    }
+}
+
+void AllocTracer::outsideTLAB2(uintptr_t klass, size_t alloc_size) {
+    if (_use_hook && _enabled && updateCounter(_allocated_bytes, alloc_size, _interval)) {
+        recordAllocation(NULL, BCI_ALLOC_OUTSIDE_TLAB, klass, alloc_size, 0);
+    }
+}
+
 void AllocTracer::recordAllocation(void* ucontext, int event_type, uintptr_t rklass,
                                    uintptr_t total_size, uintptr_t instance_size) {
-    if (_interval) {
-        // Do not record allocation unless allocated at least _interval bytes
-        while (true) {
-            u64 prev = _allocated_bytes;
-            u64 next = prev + total_size;
-            if (next < _interval) {
-                if (__sync_bool_compare_and_swap(&_allocated_bytes, prev, next)) {
-                    return;
-                }
-            } else {
-                if (__sync_bool_compare_and_swap(&_allocated_bytes, prev, next % _interval)) {
-                    break;
-                }
-            }
-        }
-    }
-
     AllocEvent event;
     event._class_id = 0;
     event._total_size = total_size;
@@ -90,18 +97,22 @@ void AllocTracer::recordAllocation(void* ucontext, int event_type, uintptr_t rkl
 
     if (VMStructs::hasClassNames()) {
         VMSymbol* symbol = VMKlass::fromHandle(rklass)->name();
-        event._class_id = Profiler::_instance.classMap()->lookup(symbol->body(), symbol->length());
+        event._class_id = Profiler::instance()->classMap()->lookup(symbol->body(), symbol->length());
     }
 
-    Profiler::_instance.recordSample(ucontext, total_size, event_type, &event);
+    Profiler::instance()->recordSample(ucontext, total_size, event_type, &event);
 }
 
 Error AllocTracer::check(Arguments& args) {
+    if (args._live) {
+        return Error("'live' option is supported on OpenJDK 11+");
+    }
+
     if (_in_new_tlab.entry() != 0 && _outside_tlab.entry() != 0) {
         return Error::OK;
     }
 
-    NativeCodeCache* libjvm = VMStructs::libjvm();
+    CodeCache* libjvm = VMStructs::libjvm();
     const void* ne;
     const void* oe;
 
@@ -118,9 +129,9 @@ Error AllocTracer::check(Arguments& args) {
         return Error("No AllocTracer symbols found. Are JDK debug symbols installed?");
     }
 
-    if (!_in_new_tlab.assign(ne) || !_outside_tlab.assign(oe)) {
-        return Error("Unable to install allocation trap");
-    }
+    _in_new_tlab.assign(ne);
+    _outside_tlab.assign(oe);
+    _in_new_tlab.pair(_outside_tlab);
 
     return Error::OK;
 }
@@ -131,18 +142,27 @@ Error AllocTracer::start(Arguments& args) {
         return error;
     }
 
-    _interval = args._interval;
+    _interval = args._alloc > 0 ? args._alloc : 0;
     _allocated_bytes = 0;
 
-    OS::installSignalHandler(SIGTRAP, signalHandler);
+    if (args._alloc_hook) {
+        if ((_trap_kind == 1 && _in_new_tlab.install((void*)inNewTLAB1) && _outside_tlab.install((void*)outsideTLAB1)) ||
+            (_trap_kind == 2 && _in_new_tlab.install((void*)inNewTLAB2) && _outside_tlab.install((void*)outsideTLAB2))) {
+            _use_hook = true;
+            return Error::OK;
+        }
+    } else if (_in_new_tlab.install() && _outside_tlab.install()) {
+        return Error::OK;
+    }
 
-    _in_new_tlab.install();
-    _outside_tlab.install();
-
-    return Error::OK;
+    return Error("Cannot install allocation breakpoints");
 }
 
 void AllocTracer::stop() {
-    _in_new_tlab.uninstall();
-    _outside_tlab.uninstall();
+    if (_use_hook) {
+        _use_hook = false;
+    } else {
+        _in_new_tlab.uninstall();
+        _outside_tlab.uninstall();
+    }
 }

src/allocTracer.h

@@ -28,31 +28,33 @@ class AllocTracer : public Engine {
     static int _trap_kind;
     static Trap _in_new_tlab;
     static Trap _outside_tlab;
+    static volatile bool _use_hook;
 
     static u64 _interval;
     static volatile u64 _allocated_bytes;
 
-    static void signalHandler(int signo, siginfo_t* siginfo, void* ucontext);
+    static void inNewTLAB1(uintptr_t klass, void* obj, size_t tlab_size, size_t alloc_size);
+    static void outsideTLAB1(uintptr_t klass, void* obj, size_t alloc_size);
+    static void inNewTLAB2(uintptr_t klass, size_t tlab_size, size_t alloc_size);
+    static void outsideTLAB2(uintptr_t klass, size_t alloc_size);
 
     static void recordAllocation(void* ucontext, int event_type, uintptr_t rklass,
                                  uintptr_t total_size, uintptr_t instance_size);
 
   public:
-    const char* name() {
-        return "alloc";
+    const char* title() {
+        return "Allocation profile";
     }
 
     const char* units() {
         return "bytes";
     }
 
-    CStack cstack() {
-        return CSTACK_NO;
-    }
-
     Error check(Arguments& args);
     Error start(Arguments& args);
     void stop();
+
+    static void trapHandler(int signo, siginfo_t* siginfo, void* ucontext);
 };
 
 #endif // _ALLOCTRACER_H

src/api/one/profiler/AsyncProfiler.java

@@ -16,7 +16,10 @@
 
 package one.profiler;
 
+import java.io.File;
+import java.io.FileOutputStream;
 import java.io.IOException;
+import java.io.InputStream;
 
 /**
  * Java API for in-process profiling. Serves as a wrapper around
@@ -39,25 +42,93 @@ public class AsyncProfiler implements AsyncProfilerMXBean {
             return instance;
         }
 
-        if (libPath == null) {
-            System.loadLibrary("asyncProfiler");
-        } else {
+        AsyncProfiler profiler = new AsyncProfiler();
+        if (libPath != null) {
             System.load(libPath);
+        } else {
+            try {
+                // No need to load library, if it has been preloaded with -agentpath
+                profiler.getVersion();
+            } catch (UnsatisfiedLinkError e) {
+                File file = extractEmbeddedLib();
+                if (file != null) {
+                    try {
+                        System.load(file.getPath());
+                    } finally {
+                        file.delete();
+                    }
+                } else {
+                    System.loadLibrary("asyncProfiler");
+                }
+            }
         }
 
-        instance = new AsyncProfiler();
-        return instance;
+        instance = profiler;
+        return profiler;
+    }
+
+    private static File extractEmbeddedLib() {
+        String resourceName = "/" + getPlatformTag() + "/libasyncProfiler.so";
+        InputStream in = AsyncProfiler.class.getResourceAsStream(resourceName);
+        if (in == null) {
+            return null;
+        }
+
+        try {
+            String extractPath = System.getProperty("one.profiler.extractPath");
+            File file = File.createTempFile("libasyncProfiler-", ".so",
+                    extractPath == null || extractPath.isEmpty() ? null : new File(extractPath));
+            try (FileOutputStream out = new FileOutputStream(file)) {
+                byte[] buf = new byte[32000];
+                for (int bytes; (bytes = in.read(buf)) >= 0; ) {
+                    out.write(buf, 0, bytes);
+                }
+            }
+            return file;
+        } catch (IOException e) {
+            throw new IllegalStateException(e);
+        } finally {
+            try {
+                in.close();
+            } catch (IOException e) {
+                // ignore
+            }
+        }
+    }
+
+    private static String getPlatformTag() {
+        String os = System.getProperty("os.name").toLowerCase();
+        String arch = System.getProperty("os.arch").toLowerCase();
+        if (os.contains("linux")) {
+            if (arch.equals("amd64") || arch.equals("x86_64") || arch.contains("x64")) {
+                return "linux-x64";
+            } else if (arch.equals("aarch64") || arch.contains("arm64")) {
+                return "linux-arm64";
+            } else if (arch.equals("aarch32") || arch.contains("arm")) {
+                return "linux-arm32";
+            } else if (arch.contains("86")) {
+                return "linux-x86";
+            } else if (arch.contains("ppc64")) {
+                return "linux-ppc64le";
+            }
+        } else if (os.contains("mac")) {
+            return "macos";
+        }
+        throw new UnsupportedOperationException("Unsupported platform: " + os + "-" + arch);
     }
 
     /**
      * Start profiling
      *
-     * @param event Profiling event, see {@link Events}
+     * @param event    Profiling event, see {@link Events}
      * @param interval Sampling interval, e.g. nanoseconds for Events.CPU
      * @throws IllegalStateException If profiler is already running
      */
     @Override
     public void start(String event, long interval) throws IllegalStateException {
+        if (event == null) {
+            throw new NullPointerException();
+        }
         start0(event, interval, true);
     }
 
@@ -65,12 +136,15 @@ public class AsyncProfiler implements AsyncProfilerMXBean {
      * Start or resume profiling without resetting collected data.
      * Note that event and interval may change since the previous profiling session.
      *
-     * @param event Profiling event, see {@link Events}
+     * @param event    Profiling event, see {@link Events}
      * @param interval Sampling interval, e.g. nanoseconds for Events.CPU
      * @throws IllegalStateException If profiler is already running
      */
     @Override
     public void resume(String event, long interval) throws IllegalStateException {
+        if (event == null) {
+            throw new NullPointerException();
+        }
         start0(event, interval, false);
     }
 
@@ -113,10 +187,13 @@ public class AsyncProfiler implements AsyncProfilerMXBean {
      * @param command Profiling command
      * @return The command result
      * @throws IllegalArgumentException If failed to parse the command
-     * @throws IOException If failed to create output file
+     * @throws IOException              If failed to create output file
      */
     @Override
-    public String execute(String command) throws IllegalArgumentException, IOException {
+    public String execute(String command) throws IllegalArgumentException, IllegalStateException, IOException {
+        if (command == null) {
+            throw new NullPointerException();
+        }
         return execute0(command);
     }
 
@@ -129,7 +206,22 @@ public class AsyncProfiler implements AsyncProfilerMXBean {
     @Override
     public String dumpCollapsed(Counter counter) {
         try {
-            return execute0("collapsed,counter=" + counter.name().toLowerCase());
+            return execute0("collapsed," + counter.name().toLowerCase());
+        } catch (IOException e) {
+            throw new IllegalStateException(e);
+        }
+    }
+
+    /**
+     * Dump collected stack traces
+     *
+     * @param maxTraces Maximum number of stack traces to dump. 0 means no limit
+     * @return Textual representation of the profile
+     */
+    @Override
+    public String dumpTraces(int maxTraces) {
+        try {
+            return execute0(maxTraces == 0 ? "traces" : "traces=" + maxTraces);
         } catch (IOException e) {
             throw new IllegalStateException(e);
         }
@@ -144,7 +236,7 @@ public class AsyncProfiler implements AsyncProfilerMXBean {
     @Override
     public String dumpFlat(int maxMethods) {
         try {
-            return execute0("flat=" + maxMethods);
+            return execute0(maxMethods == 0 ? "flat" : "flat=" + maxMethods);
         } catch (IOException e) {
             throw new IllegalStateException(e);
         }
@@ -171,7 +263,7 @@ public class AsyncProfiler implements AsyncProfilerMXBean {
     }
 
     private void filterThread(Thread thread, boolean enable) {
-        if (thread == null) {
+        if (thread == null || thread == Thread.currentThread()) {
             filterThread0(null, enable);
         } else {
             // Need to take lock to avoid race condition with a thread state change
@@ -185,7 +277,10 @@ public class AsyncProfiler implements AsyncProfilerMXBean {
     }
 
     private native void start0(String event, long interval, boolean reset) throws IllegalStateException;
+
     private native void stop0() throws IllegalStateException;
-    private native String execute0(String command) throws IllegalArgumentException, IOException;
+
+    private native String execute0(String command) throws IllegalArgumentException, IllegalStateException, IOException;
+
     private native void filterThread0(Thread thread, boolean enable);
 }

src/api/one/profiler/AsyncProfilerMXBean.java

@@ -35,8 +35,9 @@ public interface AsyncProfilerMXBean {
     long getSamples();
     String getVersion();
 
-    String execute(String command) throws IllegalArgumentException, java.io.IOException;
+    String execute(String command) throws IllegalArgumentException, IllegalStateException, java.io.IOException;
 
     String dumpCollapsed(Counter counter);
+    String dumpTraces(int maxTraces);
     String dumpFlat(int maxMethods);
 }

src/arch.h

@@ -31,28 +31,44 @@ static inline int atomicInc(volatile int& var, int increment = 1) {
     return __sync_fetch_and_add(&var, increment);
 }
 
+static inline u64 loadAcquire(u64& var) {
+    return __atomic_load_n(&var, __ATOMIC_ACQUIRE);
+}
+
+static inline void storeRelease(u64& var, u64 value) {
+    return __atomic_store_n(&var, value, __ATOMIC_RELEASE);
+}
+
 
 #if defined(__x86_64__) || defined(__i386__)
 
 typedef unsigned char instruction_t;
 const instruction_t BREAKPOINT = 0xcc;
+const int BREAKPOINT_OFFSET = 0;
 
 const int SYSCALL_SIZE = 2;
+const int FRAME_PC_SLOT = 1;
+const int ADJUST_RET = 1;
+const int PROBE_SP_LIMIT = 4;
 const int PLT_HEADER_SIZE = 16;
 const int PLT_ENTRY_SIZE = 16;
 const int PERF_REG_PC = 8;  // PERF_REG_X86_IP
 
 #define spinPause()       asm volatile("pause")
 #define rmb()             asm volatile("lfence" : : : "memory")
-#define flushCache(addr)  asm volatile("mfence; clflush (%0); mfence" : : "r"(addr) : "memory")
+#define flushCache(addr)  asm volatile("mfence; clflush (%0); mfence" : : "r" (addr) : "memory")
 
 #elif defined(__arm__) || defined(__thumb__)
 
 typedef unsigned int instruction_t;
 const instruction_t BREAKPOINT = 0xe7f001f0;
 const instruction_t BREAKPOINT_THUMB = 0xde01de01;
+const int BREAKPOINT_OFFSET = 0;
 
 const int SYSCALL_SIZE = sizeof(instruction_t);
+const int FRAME_PC_SLOT = 1;
+const int ADJUST_RET = 0;
+const int PROBE_SP_LIMIT = 0;
 const int PLT_HEADER_SIZE = 20;
 const int PLT_ENTRY_SIZE = 12;
 const int PERF_REG_PC = 15;  // PERF_REG_ARM_PC
@@ -65,16 +81,40 @@ const int PERF_REG_PC = 15;  // PERF_REG_ARM_PC
 
 typedef unsigned int instruction_t;
 const instruction_t BREAKPOINT = 0xd4200000;
+const int BREAKPOINT_OFFSET = 0;
 
 const int SYSCALL_SIZE = sizeof(instruction_t);
+const int FRAME_PC_SLOT = 1;
+const int ADJUST_RET = 0;
+const int PROBE_SP_LIMIT = 0;
 const int PLT_HEADER_SIZE = 32;
 const int PLT_ENTRY_SIZE = 16;
 const int PERF_REG_PC = 32;  // PERF_REG_ARM64_PC
 
-#define spinPause()       asm volatile("yield")
+#define spinPause()       asm volatile("isb")
 #define rmb()             asm volatile("dmb ish" : : : "memory")
 #define flushCache(addr)  __builtin___clear_cache((char*)(addr), (char*)(addr) + sizeof(instruction_t))
 
+#elif defined(__PPC64__) && (__BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__)
+
+typedef unsigned int instruction_t;
+const instruction_t BREAKPOINT = 0x7fe00008;
+// We place the break point in the third instruction slot on PPCLE as the first two are skipped if
+// the call comes from within the same compilation unit according to the LE ABI.
+const int BREAKPOINT_OFFSET = 8;
+
+const int SYSCALL_SIZE = sizeof(instruction_t);
+const int FRAME_PC_SLOT = 2;
+const int ADJUST_RET = 0;
+const int PROBE_SP_LIMIT = 0;
+const int PLT_HEADER_SIZE = 24;
+const int PLT_ENTRY_SIZE = 24;
+const int PERF_REG_PC = 32;  // PERF_REG_POWERPC_NIP
+
+#define spinPause()       asm volatile("yield") // does nothing, but using or 1,1,1 would lead to other problems
+#define rmb()             asm volatile ("sync" : : : "memory") // lwsync would do but better safe than sorry
+#define flushCache(addr)  __builtin___clear_cache((char*)(addr), (char*)(addr) + sizeof(instruction_t))
+
 #else
 
 #error "Compiling on unsupported arch"
@@ -82,4 +122,22 @@ const int PERF_REG_PC = 32;  // PERF_REG_ARM64_PC
 #endif
 
 
+// Return address signing support.
+// Apple M1 has 47 bit virtual addresses.
+#if defined(__aarch64__) && defined(__APPLE__)
+#  define ADDRESS_BITS 47
+#  define WX_MEMORY    true
+#else
+#  define WX_MEMORY    false
+#endif
+
+#ifdef ADDRESS_BITS
+static inline const void* stripPointer(const void* p) {
+    return (const void*) ((unsigned long)p & ((1UL << ADDRESS_BITS) - 1));
+}
+#else
+#  define stripPointer(p)  (p)
+#endif
+
+
 #endif // _ARCH_H

src/arguments.cpp

@@ -30,60 +30,83 @@ const Error Error::OK(NULL);
 // Extra buffer space for expanding file pattern
 const size_t EXTRA_BUF_SIZE = 512;
 
-// Statically compute hash code of a string containing up to 12 [a-z] letters
-#define HASH(s)    (HASH12(s "            "))
+static const Multiplier NANOS[] = {{'n', 1}, {'u', 1000}, {'m', 1000000}, {'s', 1000000000}, {0, 0}};
+static const Multiplier BYTES[] = {{'b', 1}, {'k', 1024}, {'m', 1048576}, {'g', 1073741824}, {0, 0}};
+static const Multiplier SECONDS[] = {{'s', 1}, {'m', 60}, {'h', 3600}, {'d', 86400}, {0, 0}};
+static const Multiplier UNIVERSAL[] = {{'n', 1}, {'u', 1000}, {'m', 1000000}, {'s', 1000000000}, {'b', 1}, {'k', 1024}, {'g', 1073741824}, {0, 0}};
 
-#define HASH12(s)  (s[0] & 31LL)       | (s[1] & 31LL) <<  5 | (s[2]  & 31LL) << 10 | (s[3]  & 31LL) << 15 | \
-                   (s[4] & 31LL) << 20 | (s[5] & 31LL) << 25 | (s[6]  & 31LL) << 30 | (s[7]  & 31LL) << 35 | \
-                   (s[8] & 31LL) << 40 | (s[9] & 31LL) << 45 | (s[10] & 31LL) << 50 | (s[11] & 31LL) << 55
+
+// Statically compute hash code of a string containing up to 12 [a-z] letters
+#define HASH(s)  ((s[0] & 31LL)       | (s[1] & 31LL) <<  5 | (s[2]  & 31LL) << 10 | (s[3]  & 31LL) << 15 | \
+                  (s[4] & 31LL) << 20 | (s[5] & 31LL) << 25 | (s[6]  & 31LL) << 30 | (s[7]  & 31LL) << 35 | \
+                  (s[8] & 31LL) << 40 | (s[9] & 31LL) << 45 | (s[10] & 31LL) << 50 | (s[11] & 31LL) << 55)
 
 // Simulate switch statement over string hashes
 #define SWITCH(arg)    long long arg_hash = hash(arg); if (0)
 
-#define CASE(s)        } else if (arg_hash == HASH(s)) {
+#define CASE(s)        } else if (arg_hash == HASH(s "            ")) {
 
-#define CASE2(s1, s2)  } else if (arg_hash == HASH(s1) || arg_hash == HASH(s2)) {
+#define DEFAULT()      } else {
 
 
 // Parses agent arguments.
 // The format of the string is:
 //     arg[,arg...]
 // where arg is one of the following options:
-//     start           - start profiling
-//     resume          - start or resume profiling without resetting collected data
-//     stop            - stop profiling
-//     check           - check if the specified profiling event is available
-//     status          - print profiling status (inactive / running for X seconds)
-//     list            - show the list of available profiling events
-//     version[=full]  - display the agent version
-//     event=EVENT     - which event to trace (cpu, alloc, lock, cache-misses etc.)
-//     collapsed[=C]   - dump collapsed stacks (the format used by FlameGraph script)
-//     html[=C]        - produce Flame Graph in HTML format
-//     tree[=C]        - produce call tree in HTML format
-//                       C is counter type: 'samples' or 'total'
-//     jfr             - dump events in Java Flight Recorder format
-//     flat[=N]        - dump top N methods (aka flat profile)
-//     interval=N      - sampling interval in ns (default: 10'000'000, i.e. 10 ms)
-//     jstackdepth=N   - maximum Java stack depth (default: 2048)
-//     safemode=BITS   - disable stack recovery techniques (default: 0, i.e. everything enabled)
-//     file=FILENAME   - output file name for dumping
-//     filter=FILTER   - thread filter
-//     threads         - profile different threads separately
-//     cstack=MODE     - how to collect C stack frames in addition to Java stack
-//                       MODE is 'fp' (Frame Pointer), 'lbr' (Last Branch Record) or 'no'
-//     allkernel       - include only kernel-mode events
-//     alluser         - include only user-mode events
-//     simple          - simple class names instead of FQN
-//     dot             - dotted class names
-//     sig             - print method signatures
-//     ann             - annotate Java method names
-//     include=PATTERN - include stack traces containing PATTERN
-//     exclude=PATTERN - exclude stack traces containing PATTERN
-//     begin=FUNCTION  - begin profiling when FUNCTION is executed
-//     end=FUNCTION    - end profiling when FUNCTION is executed
-//     title=TITLE     - FlameGraph title
-//     minwidth=PCT    - FlameGraph minimum frame width in percent
-//     reverse         - generate stack-reversed FlameGraph / Call tree
+//     start            - start profiling
+//     resume           - start or resume profiling without resetting collected data
+//     stop             - stop profiling
+//     dump             - dump collected data without stopping profiling session
+//     check            - check if the specified profiling event is available
+//     status           - print profiling status (inactive / running for X seconds)
+//     meminfo          - print profiler memory stats
+//     list             - show the list of available profiling events
+//     version[=full]   - display the agent version
+//     event=EVENT      - which event to trace (cpu, wall, cache-misses, etc.)
+//     alloc[=BYTES]    - profile allocations with BYTES interval
+//     live             - build allocation profile from live objects only
+//     lock[=DURATION]  - profile contended locks longer than DURATION ns
+//     collapsed        - dump collapsed stacks (the format used by FlameGraph script)
+//     flamegraph       - produce Flame Graph in HTML format
+//     tree             - produce call tree in HTML format
+//     jfr              - dump events in Java Flight Recorder format
+//     jfrsync[=CONFIG] - start Java Flight Recording with the given config along with the profiler 
+//     traces[=N]       - dump top N call traces
+//     flat[=N]         - dump top N methods (aka flat profile)
+//     samples          - count the number of samples (default)
+//     total            - count the total value (time, bytes, etc.) instead of samples
+//     chunksize=N      - approximate size of JFR chunk in bytes (default: 100 MB)
+//     chunktime=N      - duration of JFR chunk in seconds (default: 1 hour)
+//     timeout=TIME     - automatically stop profiler at TIME (absolute or relative)
+//     loop=TIME        - run profiler in a loop (continuous profiling)
+//     interval=N       - sampling interval in ns (default: 10'000'000, i.e. 10 ms)
+//     jstackdepth=N    - maximum Java stack depth (default: 2048)
+//     safemode=BITS    - disable stack recovery techniques (default: 0, i.e. everything enabled)
+//     file=FILENAME    - output file name for dumping
+//     log=FILENAME     - log warnings and errors to the given dedicated stream
+//     loglevel=LEVEL   - logging level: TRACE, DEBUG, INFO, WARN, ERROR, or NONE
+//     server=ADDRESS   - start insecure HTTP server at ADDRESS/PORT
+//     filter=FILTER    - thread filter
+//     threads          - profile different threads separately
+//     sched            - group threads by scheduling policy
+//     cstack=MODE      - how to collect C stack frames in addition to Java stack
+//                        MODE is 'fp' (Frame Pointer), 'dwarf', 'lbr' (Last Branch Record) or 'no'
+//     allkernel        - include only kernel-mode events
+//     alluser          - include only user-mode events
+//     fdtransfer       - use fdtransfer to pass fds to the profiler
+//     simple           - simple class names instead of FQN
+//     dot              - dotted class names
+//     sig              - print method signatures
+//     ann              - annotate Java methods
+//     lib              - prepend library names
+//     mcache           - max age of jmethodID cache (default: 0 = disabled)
+//     include=PATTERN  - include stack traces containing PATTERN
+//     exclude=PATTERN  - exclude stack traces containing PATTERN
+//     begin=FUNCTION   - begin profiling when FUNCTION is executed
+//     end=FUNCTION     - end profiling when FUNCTION is executed
+//     title=TITLE      - FlameGraph title
+//     minwidth=PCT     - FlameGraph minimum frame width in percent
+//     reverse          - generate stack-reversed FlameGraph / Call tree
 //
 // It is possible to specify multiple dump options at the same time
 
@@ -94,13 +117,15 @@ Error Arguments::parse(const char* args) {
 
     size_t len = strlen(args);
     free(_buf);
-    _buf = (char*)malloc(len + EXTRA_BUF_SIZE);
+    _buf = (char*)malloc(len + EXTRA_BUF_SIZE + 1);
     if (_buf == NULL) {
         return Error("Not enough memory to parse arguments");
     }
-    strcpy(_buf, args);
+    char* args_copy = strcpy(_buf + EXTRA_BUF_SIZE, args);
 
-    for (char* arg = strtok(_buf, ","); arg != NULL; arg = strtok(NULL, ",")) {
+    const char* msg = NULL;    
+
+    for (char* arg = strtok(args_copy, ","); arg != NULL; arg = strtok(NULL, ",")) {
         char* value = strchr(arg, '=');
         if (value != NULL) *value++ = 0;
 
@@ -115,12 +140,18 @@ Error Arguments::parse(const char* args) {
             CASE("stop")
                 _action = ACTION_STOP;
 
+            CASE("dump")
+                _action = ACTION_DUMP;
+
             CASE("check")
                 _action = ACTION_CHECK;
 
             CASE("status")
                 _action = ACTION_STATUS;
 
+            CASE("meminfo")
+                _action = ACTION_MEMINFO;
+
             CASE("list")
                 _action = ACTION_LIST;
 
@@ -128,67 +159,171 @@ Error Arguments::parse(const char* args) {
                 _action = value == NULL ? ACTION_VERSION : ACTION_FULL_VERSION;
 
             // Output formats
-            CASE2("collapsed", "folded")
+            CASE("collapsed")
                 _output = OUTPUT_COLLAPSED;
-                _counter = value == NULL || strcmp(value, "samples") == 0 ? COUNTER_SAMPLES : COUNTER_TOTAL;
 
-            CASE2("flamegraph", "html")
+            CASE("flamegraph")
                 _output = OUTPUT_FLAMEGRAPH;
-                _counter = value == NULL || strcmp(value, "samples") == 0 ? COUNTER_SAMPLES : COUNTER_TOTAL;
 
             CASE("tree")
                 _output = OUTPUT_TREE;
-                _counter = value == NULL || strcmp(value, "samples") == 0 ? COUNTER_SAMPLES : COUNTER_TOTAL;
 
             CASE("jfr")
                 _output = OUTPUT_JFR;
+                if (value != NULL) {
+                    _jfr_options = (int)strtol(value, NULL, 0);
+                }
+
+            CASE("jfrsync")
+                _output = OUTPUT_JFR;
+                _jfr_options = JFR_SYNC_OPTS;
+                _jfr_sync = value == NULL ? "default" : value;
+
+            CASE("traces")
+                _output = OUTPUT_TEXT;
+                _dump_traces = value == NULL ? INT_MAX : atoi(value);
 
             CASE("flat")
-                _output = OUTPUT_FLAT;
+                _output = OUTPUT_TEXT;
                 _dump_flat = value == NULL ? INT_MAX : atoi(value);
 
+            CASE("samples")
+                _counter = COUNTER_SAMPLES;
+
+            CASE("total")
+                _counter = COUNTER_TOTAL;
+
+            CASE("chunksize")
+                if (value == NULL || (_chunk_size = parseUnits(value, BYTES)) < 0) {
+                    msg = "Invalid chunksize";
+                }
+
+            CASE("chunktime")
+                if (value == NULL || (_chunk_time = parseUnits(value, SECONDS)) < 0) {
+                    msg = "Invalid chunktime";
+                }
+
             // Basic options
             CASE("event")
                 if (value == NULL || value[0] == 0) {
-                    return Error("event must not be empty");
+                    msg = "event must not be empty";
+                } else if (strcmp(value, EVENT_ALLOC) == 0) {
+                    if (_alloc < 0) _alloc = 0;
+                } else if (strcmp(value, EVENT_LOCK) == 0) {
+                    if (_lock < 0) _lock = 0;
+                } else if (_event != NULL) {
+                    msg = "Duplicate event argument";
+                } else {
+                    _event = value;
                 }
 
-                if (!addEvent(value)) {
-                    return Error("multiple incompatible events");
+            CASE("timeout")
+                if (value == NULL || (_timeout = parseTimeout(value)) == -1 || !_persistent) {
+                    msg = "Invalid timeout";
                 }
 
+            CASE("loop")
+                _loop = true;
+                if (value == NULL || (_timeout = parseTimeout(value)) == -1 || !_persistent) {
+                    msg = "Invalid loop duration";
+                }
+
+            CASE("alloc")
+                _alloc = value == NULL ? 0 : parseUnits(value, BYTES);
+
+            CASE("lock")
+                _lock = value == NULL ? 0 : parseUnits(value, NANOS);
+
             CASE("interval")
-                if (value == NULL || (_interval = parseUnits(value)) <= 0) {
-                    return Error("Invalid interval");
+                if (value == NULL || (_interval = parseUnits(value, UNIVERSAL)) <= 0) {
+                    msg = "Invalid interval";
                 }
 
             CASE("jstackdepth")
                 if (value == NULL || (_jstackdepth = atoi(value)) <= 0) {
-                    return Error("jstackdepth must be > 0");
+                    msg = "jstackdepth must be > 0";
                 }
 
             CASE("safemode")
-                _safe_mode = value == NULL ? INT_MAX : atoi(value);
+                _safe_mode = value == NULL ? INT_MAX : (int)strtol(value, NULL, 0);
 
             CASE("file")
                 if (value == NULL || value[0] == 0) {
-                    return Error("file must not be empty");
+                    msg = "file must not be empty";
                 }
                 _file = value;
 
+            CASE("log")
+                _log = value == NULL || value[0] == 0 ? NULL : value;
+
+            CASE("loglevel")
+                if (value == NULL || value[0] == 0) {
+                    msg = "loglevel must not be empty";
+                }
+                _loglevel = value;
+
+            CASE("server")
+                if (value == NULL || value[0] == 0) {
+                    msg = "server address must not be empty";
+                }
+                _server = value;
+
+            CASE("fdtransfer")
+                _fdtransfer = true;
+                if (value == NULL || value[0] == 0) {
+                    msg = "fdtransfer path must not be empty";
+                }
+                _fdtransfer_path = value;
+
+            CASE("cloud")
+                // Meta option for continuous eBPF-assisted cloud profiling
+                if (_action == ACTION_NONE) {
+                    _action = ACTION_START;
+                }
+                if (_event == NULL) {
+                    _event = EVENT_BPF;
+                    _sched = true;
+                    _alloc_hook = true;
+                }
+                if (_fdtransfer_path == NULL) {
+                    _fdtransfer = true;
+                    _fdtransfer_path = "/one/profile/profile.sock";
+                }
+                if (_file == NULL) {
+                    _file = "/one/logs/%{cloud_image}-%t.jfr";
+                }
+                if (_timeout == 0) {
+                    _loop = true;
+                    _timeout = 0xff0000ff;  // rotate at 00:00
+                }
+                if (_chunk_time == 0) {
+                    _chunk_time = 300;  // 5 min
+                }
+
             // Filters
             CASE("filter")
                 _filter = value == NULL ? "" : value;
 
             CASE("include")
-                if (value != NULL) appendToEmbeddedList(_include, value);
+                // Workaround -Wstringop-overflow warning
+                if (value == arg + 8) appendToEmbeddedList(_include, arg + 8);
 
             CASE("exclude")
-                if (value != NULL) appendToEmbeddedList(_exclude, value);
+                // Workaround -Wstringop-overflow warning
+                if (value == arg + 8) appendToEmbeddedList(_exclude, arg + 8);
 
             CASE("threads")
                 _threads = true;
 
+            CASE("sched")
+                _sched = true;
+
+            CASE("live")
+                _live = true;
+
+            CASE("allochook")
+                _alloc_hook = true;
+
             CASE("allkernel")
                 _ring = RING_KERNEL;
 
@@ -199,6 +334,8 @@ Error Arguments::parse(const char* args) {
                 if (value != NULL) {
                     if (value[0] == 'n') {
                         _cstack = CSTACK_NO;
+                    } else if (value[0] == 'd') {
+                        _cstack = CSTACK_DWARF;
                     } else if (value[0] == 'l') {
                         _cstack = CSTACK_LBR;
                     } else {
@@ -219,6 +356,12 @@ Error Arguments::parse(const char* args) {
             CASE("ann")
                 _style |= STYLE_ANNOTATE;
 
+            CASE("lib")
+                _style |= STYLE_LIB_NAMES;
+
+            CASE("mcache")
+                _mcache = value == NULL ? 1 : (unsigned char)strtol(value, NULL, 0);
+
             CASE("begin")
                 _begin = value;
 
@@ -227,45 +370,49 @@ Error Arguments::parse(const char* args) {
 
             // FlameGraph options
             CASE("title")
-                if (value != NULL) _title = value;
+                _title = value;
 
             CASE("minwidth")
                 if (value != NULL) _minwidth = atof(value);
 
             CASE("reverse")
                 _reverse = true;
+
+            DEFAULT()
+                if (_unknown_arg == NULL) _unknown_arg = arg;
         }
     }
 
-    if (_file != NULL && strchr(_file, '%') != NULL) {
-        _file = expandFilePattern(_buf + len + 1, EXTRA_BUF_SIZE - 1, _file);
+    // Return error only after parsing all arguments, when 'log' is already set
+    if (msg != NULL) {
+        return Error(msg);
+    }
+
+    if (_event == NULL && _alloc < 0 && _lock < 0) {
+        _event = EVENT_CPU;
     }
 
     if (_file != NULL && _output == OUTPUT_NONE) {
         _output = detectOutputFormat(_file);
+        if (_output == OUTPUT_SVG) {
+            return Error("SVG format is obsolete, use .html for FlameGraph");
+        }
+        _dump_traces = 100;
         _dump_flat = 200;
     }
 
-    if (_output != OUTPUT_NONE && (_action == ACTION_NONE || _action == ACTION_STOP)) {
+    if (_action == ACTION_NONE && _output != OUTPUT_NONE) {
         _action = ACTION_DUMP;
     }
 
     return Error::OK;
 }
 
-bool Arguments::addEvent(const char* event) {
-    if (strcmp(event, EVENT_ALLOC) == 0) {
-        _events |= EK_ALLOC;
-    } else if (strcmp(event, EVENT_LOCK) == 0) {
-        _events |= EK_LOCK;
-    } else {
-        if (_events & EK_CPU) {
-            return false;
-        }
-        _events |= EK_CPU;
-        _event_desc = event;
+const char* Arguments::file() {
+    if (_file != NULL && strchr(_file, '%') != NULL) {
+        return expandFilePattern(_file);
     }
-    return true;
+    return _file;
 }
 
 // The linked list of string offsets is embedded right into _buf array
@@ -283,11 +430,14 @@ long long Arguments::hash(const char* arg) {
     return h;
 }
 
-// Expands %p to the process id
-//         %t to the timestamp
-const char* Arguments::expandFilePattern(char* dest, size_t max_size, const char* pattern) {
-    char* ptr = dest;
-    char* end = dest + max_size - 1;
+// Expands the following patterns:
+//   %p       process id
+//   %t       timestamp (yyyyMMdd-hhmmss)
+//   %n{MAX}  sequence number
+//   %{ENV}   environment variable
+const char* Arguments::expandFilePattern(const char* pattern) {
+    char* ptr = _buf;
+    char* end = _buf + EXTRA_BUF_SIZE - 1;
 
     while (ptr < end && *pattern != 0) {
         char c = *pattern++;
@@ -306,13 +456,35 @@ const char* Arguments::expandFilePattern(char* dest, size_t max_size, const char
                                 t.tm_year + 1900, t.tm_mon + 1, t.tm_mday,
                                 t.tm_hour, t.tm_min, t.tm_sec);
                 continue;
+            } else if (c == 'n') {
+                unsigned int max_files = 0;
+                const char* p;
+                if (*pattern == '{' && (p = strchr(pattern, '}')) != NULL) {
+                    max_files = atoi(pattern + 1);
+                    pattern = p + 1;
+                }
+                ptr += snprintf(ptr, end - ptr, "%u", max_files > 0 ? _file_num % max_files : _file_num);
+                continue;
+            } else if (c == '{') {
+                char env_key[128];
+                const char* p = strchr(pattern, '}');
+                if (p != NULL && p - pattern < sizeof(env_key)) {
+                    memcpy(env_key, pattern, p - pattern);
+                    env_key[p - pattern] = 0;
+                    const char* env_value = getenv(env_key);
+                    if (env_value != NULL) {
+                        ptr += snprintf(ptr, end - ptr, "%s", env_value);
+                        pattern = p + 1;
+                        continue;
+                    }
+                }
             }
         }
         *ptr++ = c;
     }
 
-    *ptr = 0;
-    return dest;
+    *(ptr < end ? ptr : end) = 0;
+    return _buf;
 }
 
 Output Arguments::detectOutputFormat(const char* file) {
@@ -324,31 +496,49 @@ Output Arguments::detectOutputFormat(const char* file) {
             return OUTPUT_JFR;
         } else if (strcmp(ext, ".collapsed") == 0 || strcmp(ext, ".folded") == 0) {
             return OUTPUT_COLLAPSED;
+        } else if (strcmp(ext, ".svg") == 0) {
+            return OUTPUT_SVG;
         }
     }
-    return OUTPUT_FLAT;
+    return OUTPUT_TEXT;
 }
 
-long Arguments::parseUnits(const char* str) {
+long Arguments::parseUnits(const char* str, const Multiplier* multipliers) {
     char* end;
     long result = strtol(str, &end, 0);
+    if (end == str) {
+        return -1;
+    }
 
-    switch (*end) {
-        case 0:
-            return result;
-        case 'K': case 'k':
-        case 'U': case 'u': // microseconds
-            return result * 1000;
-        case 'M': case 'm': // million, megabytes or milliseconds
-            return result * 1000000;
-        case 'G': case 'g':
-        case 'S': case 's': // seconds
-            return result * 1000000000;
+    char c = *end;
+    if (c == 0) {
+        return result;
+    }
+    if (c >= 'A' && c <= 'Z') {
+        c += 'a' - 'A';
+    }
+
+    for (const Multiplier* m = multipliers; m->symbol; m++) {
+        if (c == m->symbol) {
+            return result * m->multiplier;
+        }
     }
 
     return -1;
 }
 
+int Arguments::parseTimeout(const char* str) {
+    const char* p = strchr(str, ':');
+    if (p == NULL) {
+        return parseUnits(str, SECONDS);
+    }
+
+    int hh = str[0] >= '0' && str[0] <= '2' ? atoi(str) : 0xff;
+    int mm = p[1] >= '0' && p[1] <= '5' ? atoi(p + 1) : 0xff;
+    int ss = (p = strchr(p + 1, ':')) != NULL && p[1] >= '0' && p[1] <= '5' ? atoi(p + 1) : 0xff;
+    return 0xff000000 | hh << 16 | mm << 8 | ss;
+}
+
 Arguments::~Arguments() {
     if (!_shared) free(_buf);
 }

src/arguments.h

@@ -20,27 +20,29 @@
 #include <stddef.h>
 
 
-const long DEFAULT_INTERVAL = 10000000;  // 10 ms
+const long DEFAULT_INTERVAL = 10000000;      // 10 ms
+const long DEFAULT_ALLOC_INTERVAL = 524287;  // 512 KiB
 const int DEFAULT_JSTACKDEPTH = 2048;
 
 const char* const EVENT_CPU    = "cpu";
+const char* const EVENT_BPF    = "bpf";
 const char* const EVENT_ALLOC  = "alloc";
 const char* const EVENT_LOCK   = "lock";
 const char* const EVENT_WALL   = "wall";
 const char* const EVENT_ITIMER = "itimer";
-const char* const EVENT_JSTACK = "jstack";
 
 enum Action {
     ACTION_NONE,
     ACTION_START,
     ACTION_RESUME,
     ACTION_STOP,
+    ACTION_DUMP,
     ACTION_CHECK,
     ACTION_STATUS,
+    ACTION_MEMINFO,
     ACTION_LIST,
     ACTION_VERSION,
-    ACTION_FULL_VERSION,
-    ACTION_DUMP
+    ACTION_FULL_VERSION
 };
 
 enum Counter {
@@ -54,35 +56,48 @@ enum Ring {
     RING_USER
 };
 
-enum EventKind {
-    EK_CPU   = 1,
-    EK_ALLOC = 2,
-    EK_LOCK  = 4
-};
-
 enum Style {
-    STYLE_SIMPLE     = 1,
-    STYLE_DOTTED     = 2,
-    STYLE_SIGNATURES = 4,
-    STYLE_ANNOTATE   = 8
+    STYLE_SIMPLE       = 1,
+    STYLE_DOTTED       = 2,
+    STYLE_SIGNATURES   = 4,
+    STYLE_ANNOTATE     = 8,
+    STYLE_LIB_NAMES    = 16,
+    STYLE_NO_SEMICOLON = 32
 };
 
 enum CStack {
     CSTACK_DEFAULT,
     CSTACK_NO,
     CSTACK_FP,
+    CSTACK_DWARF,
     CSTACK_LBR
 };
 
 enum Output {
     OUTPUT_NONE,
-    OUTPUT_FLAT,
+    OUTPUT_TEXT,
+    OUTPUT_SVG,  // obsolete
     OUTPUT_COLLAPSED,
     OUTPUT_FLAMEGRAPH,
     OUTPUT_TREE,
     OUTPUT_JFR
 };
 
+enum JfrOption {
+    NO_SYSTEM_INFO  = 0x1,
+    NO_SYSTEM_PROPS = 0x2,
+    NO_NATIVE_LIBS  = 0x4,
+    NO_CPU_LOAD     = 0x8,
+
+    JFR_SYNC_OPTS   = NO_SYSTEM_INFO | NO_SYSTEM_PROPS | NO_NATIVE_LIBS | NO_CPU_LOAD
+};
+
+
+struct Multiplier {
+    char symbol;
+    long multiplier;
+};
+
 
 class Error {
   private:
@@ -108,32 +123,53 @@ class Arguments {
   private:
     char* _buf;
     bool _shared;
+    bool _persistent;
 
     void appendToEmbeddedList(int& list, char* value);
+    const char* expandFilePattern(const char* pattern);
 
     static long long hash(const char* arg);
-    static const char* expandFilePattern(char* dest, size_t max_size, const char* pattern);
     static Output detectOutputFormat(const char* file);
-    static long parseUnits(const char* str);
+    static long parseUnits(const char* str, const Multiplier* multipliers);
+    static int parseTimeout(const char* str);
 
   public:
     Action _action;
     Counter _counter;
     Ring _ring;
-    int _events;
-    const char* _event_desc;
+    const char* _event;
+    int _timeout;
     long _interval;
+    long _alloc;
+    long _lock;
     int  _jstackdepth;
     int _safe_mode;
     const char* _file;
+    const char* _log;
+    const char* _loglevel;
+    const char* _unknown_arg;
+    const char* _server;
     const char* _filter;
     int _include;
     int _exclude;
+    unsigned char _mcache;
+    bool _loop;
     bool _threads;
+    bool _sched;
+    bool _live;
+    bool _alloc_hook;
+    bool _fdtransfer;
+    const char* _fdtransfer_path;
     int _style;
     CStack _cstack;
     Output _output;
+    long _chunk_size;
+    long _chunk_time;
+    const char* _jfr_sync;
+    int _jfr_options;
+    int _dump_traces;
     int _dump_flat;
+    unsigned int _file_num;
     const char* _begin;
     const char* _end;
     // FlameGraph parameters
@@ -141,28 +177,49 @@ class Arguments {
     double _minwidth;
     bool _reverse;
 
-    Arguments() :
+    Arguments(bool persistent = false) :
         _buf(NULL),
         _shared(false),
+        _persistent(persistent),
         _action(ACTION_NONE),
         _counter(COUNTER_SAMPLES),
         _ring(RING_ANY),
-        _events(0),
-        _event_desc(NULL),
+        _event(NULL),
+        _timeout(0),
         _interval(0),
+        _alloc(-1),
+        _lock(-1),
         _jstackdepth(DEFAULT_JSTACKDEPTH),
         _safe_mode(0),
         _file(NULL),
+        _log(NULL),
+        _loglevel(NULL),
+        _unknown_arg(NULL),
+        _server(NULL),
         _filter(NULL),
         _include(0),
         _exclude(0),
+        _mcache(0),
+        _loop(false),
         _threads(false),
+        _sched(false),
+        _live(false),
+        _alloc_hook(false),
+        _fdtransfer(false),
+        _fdtransfer_path(NULL),
         _style(0),
         _cstack(CSTACK_DEFAULT),
         _output(OUTPUT_NONE),
+        _chunk_size(100 * 1024 * 1024),
+        _chunk_time(0),
+        _jfr_sync(NULL),
+        _jfr_options(0),
+        _dump_traces(0),
+        _dump_flat(0),
+        _file_num(0),
         _begin(NULL),
         _end(NULL),
-        _title("Flame Graph"),
+        _title(NULL),
         _minwidth(0),
         _reverse(false) {
     }
@@ -173,7 +230,16 @@ class Arguments {
 
     Error parse(const char* args);
 
-    bool addEvent(const char* event);
+    const char* file();
+
+    bool hasOutputFile() const {
+        return _file != NULL &&
+            (_action == ACTION_STOP || _action == ACTION_DUMP ? _output != OUTPUT_JFR : _action >= ACTION_STATUS);
+    }
+
+    bool hasOption(JfrOption option) const {
+        return (_jfr_options & option) != 0;
+    }
 
     friend class FrameName;
     friend class Recording;

src/bpfClient.cpp

@@ -0,0 +1,138 @@
+/*
+ * Copyright 2021 Andrei Pangin
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <sched.h>
+#include <unistd.h>
+#include <sys/mman.h>
+#include "bpfClient.h"
+#include "fdtransferClient.h"
+#include "os.h"
+#include "profiler.h"
+#include "stackWalker.h"
+#include "vmStructs.h"
+
+
+// Use different profiling signal to allow running two profilers together
+const int BPF_SIGNAL = SIGSTKFLT;
+
+struct BpfStackTrace {
+    u32 pid;
+    u32 tid;
+    u64 counter;
+    u16 event_type;
+    u16 sched_policy;
+    u32 depth;
+    u64 ip[0];
+};
+
+struct BpfMap {
+    char* addr;
+    size_t size;
+    u32 salt;
+    u32 mask;
+    u32 entry_size;
+
+    BpfStackTrace* getStackForThread(u32 tid) const {
+        char* base = __atomic_load_n(&addr, __ATOMIC_ACQUIRE);
+        if (base == NULL) {
+            return NULL;
+        }
+        size_t index = (salt + tid) & mask;
+        return (BpfStackTrace*)(base + index * entry_size);
+    }
+};
+
+static BpfMap _bpf_map = {0};
+
+static unsigned int _interval;
+static unsigned int _counter;
+
+
+void BpfClient::signalHandler(int signo, siginfo_t* siginfo, void* ucontext) {
+    if (!_enabled) return;
+
+    if (_interval <= 1 || __sync_add_and_fetch(&_counter, 1) % _interval == 0) {
+        ExecutionEvent event;
+        Profiler::instance()->recordSample(ucontext, _interval, 0, &event);
+    }
+}
+
+Error BpfClient::check(Arguments& args) {
+    return Error::OK;
+}
+
+Error BpfClient::start(Arguments& args) {
+    OS::installSignalHandler(BPF_SIGNAL, signalHandler);
+
+    struct bpfmap_params params;
+    int fd = FdTransferClient::requestBpfMapFd(&params);
+    if (fd < 0) {
+        return Error("Failed to request bpf map");
+    }
+
+    _interval = args._interval;
+    _counter = 0;
+
+    _bpf_map.salt = params.salt;
+    _bpf_map.mask = params.num_entries - 1;
+    _bpf_map.entry_size = params.entry_size;
+    _bpf_map.size = (size_t)params.entry_size * params.num_entries;
+
+    char* addr = (char*)mmap(NULL, _bpf_map.size, PROT_READ, MAP_SHARED, fd, 0);
+    if (addr == MAP_FAILED) {
+        close(fd);
+        return Error("Failed to mmap stack trace buffer");
+    }
+
+    close(fd);
+    __atomic_store_n(&_bpf_map.addr, addr, __ATOMIC_RELEASE);
+
+    return Error::OK;
+}
+
+void BpfClient::stop() {
+    OS::installSignalHandler(BPF_SIGNAL, NULL, SIG_IGN);
+
+    char* addr = __atomic_exchange_n(&_bpf_map.addr, NULL, __ATOMIC_ACQ_REL);
+    munmap(addr, _bpf_map.size);
+}
+
+int BpfClient::walk(int tid, void* ucontext, const void** callchain, int max_depth, StackContext* java_ctx) {
+    int depth = 0;
+
+    // Fill kernel frames from bpf map
+    BpfStackTrace* trace = _bpf_map.getStackForThread(tid);
+    if (trace != NULL && trace->tid == tid) {
+        int limit = trace->depth < max_depth ? trace->depth : max_depth;
+        while (depth < limit && (intptr_t)trace->ip[depth] < 0) {
+            callchain[depth] = (const void*)trace->ip[depth];
+            depth++;
+        }
+    }
+
+    // Add user-space frames by manual stack walking
+    depth += StackWalker::walkDwarf(ucontext, callchain + depth, max_depth - depth, java_ctx);
+
+    return depth;
+}
+
+const char* BpfClient::schedPolicy(int tid) {
+    BpfStackTrace* trace = _bpf_map.getStackForThread(tid);
+    if (trace == NULL || trace->tid != tid || trace->sched_policy < SCHED_BATCH) {
+        return "SCHED_OTHER";
+    }
+    return trace->sched_policy >= SCHED_IDLE ? "SCHED_IDLE" : "SCHED_BATCH"; 
+}

src/bpfClient.h

@@ -14,28 +14,34 @@
  * limitations under the License.
  */
 
-#ifndef _JSTACK_H
-#define _JSTACK_H
+#ifndef _BPFCLIENT_H
+#define _BPFCLIENT_H
 
 #include <signal.h>
 #include "engine.h"
 
 
-class JStack : public Engine {
+class BpfClient : public Engine {
   private:
+
     static void signalHandler(int signo, siginfo_t* siginfo, void* ucontext);
 
   public:
-    const char* name() {
-        return EVENT_JSTACK;
+    const char* title() {
+        return "CPU profile";
     }
 
     const char* units() {
-        return "samples";
+        return "cycles";
     }
 
+    Error check(Arguments& args);
     Error start(Arguments& args);
     void stop();
+
+    static int walk(int tid, void* ucontext, const void** callchain, int max_depth, StackContext* java_ctx);
+
+    static const char* schedPolicy(int tid);
 };
 
-#endif // _JSTACK_H
+#endif // _BPFCLIENT_H

src/callTraceStorage.cpp

@@ -15,36 +15,35 @@
  */
 
 #include <string.h>
-#include <unistd.h>
 #include "callTraceStorage.h"
 #include "os.h"
 
 
-static const u32 INITIAL_CAPACITY = 65536;
+static const u32 CAPACITY = 131072;
 static const u32 CALL_TRACE_CHUNK = 8 * 1024 * 1024;
-static const size_t PAGE_ALIGNMENT = sysconf(_SC_PAGESIZE) - 1;
+static const u32 OVERFLOW_TRACE_ID = 0x7fffffff;
 
 
 class LongHashTable {
   private:
     LongHashTable* _prev;
     void* _padding0;
-    u32 _capacity;
+    u32 _base;
     u32 _padding1[15];
     volatile u32 _size;
     u32 _padding2[15];
 
-    static size_t getSize(u32 capacity) {
-        size_t size = sizeof(LongHashTable) + (sizeof(u64) + sizeof(CallTraceSample)) * capacity;
-        return (size + PAGE_ALIGNMENT) & ~PAGE_ALIGNMENT;
+    static size_t getSize() {
+        size_t size = sizeof(LongHashTable) + (sizeof(u64) + sizeof(CallTraceSample)) * CAPACITY;
+        return (size + OS::page_mask) & ~OS::page_mask;
     }
 
   public:
-    static LongHashTable* allocate(LongHashTable* prev, u32 capacity) {
-        LongHashTable* table = (LongHashTable*)OS::safeAlloc(getSize(capacity));
+    static LongHashTable* allocate(LongHashTable* prev, u32 base) {
+        LongHashTable* table = (LongHashTable*)OS::safeAlloc(getSize());
         if (table != NULL) {
             table->_prev = prev;
-            table->_capacity = capacity;
+            table->_base = base;
             table->_size = 0;
         }
         return table;
@@ -52,19 +51,27 @@ class LongHashTable {
 
     LongHashTable* destroy() {
         LongHashTable* prev = _prev;
-        OS::safeFree(this, getSize(_capacity));
+        OS::safeFree(this, getSize());
         return prev;
     }
 
-    LongHashTable* prev() {
+    size_t usedMemory() const {
+        return getSize();
+    }
+
+    LongHashTable* trim() {
+        return __atomic_exchange_n(&_prev, NULL, __ATOMIC_ACQ_REL);
+    }
+
+    LongHashTable* prev() const {
         return _prev;
     }
 
-    u32 capacity() {
-        return _capacity;
+    u32 base() const {
+        return _base;
     }
 
-    u32 size() {
+    u32 size() const {
         return _size;
     }
 
@@ -77,18 +84,21 @@ class LongHashTable {
     }
 
     CallTraceSample* values() {
-        return (CallTraceSample*)(keys() + _capacity);
+        return (CallTraceSample*)(keys() + CAPACITY);
     }
 
     void clear() {
-        memset(keys(), 0, (sizeof(u64) + sizeof(CallTraceSample)) * _capacity);
+        memset(keys(), 0, (sizeof(u64) + sizeof(CallTraceSample)) * CAPACITY);
         _size = 0;
     }
 };
 
 
+CallTrace CallTraceStorage::_overflow_trace = {1, {BCI_ERROR, (jmethodID)"storage_overflow"}};
+
 CallTraceStorage::CallTraceStorage() : _allocator(CALL_TRACE_CHUNK) {
-    _current_table = LongHashTable::allocate(NULL, INITIAL_CAPACITY);
+    _current_table = LongHashTable::allocate(NULL, 1);
+    _overflow = 0;
 }
 
 CallTraceStorage::~CallTraceStorage() {
@@ -103,29 +113,61 @@ void CallTraceStorage::clear() {
     }
     _current_table->clear();
     _allocator.clear();
+    _overflow = 0;
+}
+
+size_t CallTraceStorage::usedMemory() {
+    size_t bytes = _allocator.usedMemory();
+    for (LongHashTable* table = _current_table; table != NULL; table = table->prev()) {
+        bytes += table->usedMemory();
+    }
+    return bytes;
+}
+
+Chunk* CallTraceStorage::trimAllocator() {
+    return _allocator.trim();
+}
+
+LongHashTable* CallTraceStorage::trimTable() {
+    return _current_table->trim();
+}
+
+void CallTraceStorage::freeMemory(Chunk* chunk, LongHashTable* table) {
+    _allocator.freeChain(chunk);
+    while (table != NULL) {
+        table = table->destroy();
+    }
 }
 
 void CallTraceStorage::collectTraces(std::map<u32, CallTrace*>& map) {
     for (LongHashTable* table = _current_table; table != NULL; table = table->prev()) {
         u64* keys = table->keys();
         CallTraceSample* values = table->values();
-        u32 capacity = table->capacity();
+        u32 base = table->base();
 
-        for (u32 slot = 0; slot < capacity; slot++) {
-            if (keys[slot] != 0) {
-                map[capacity - (INITIAL_CAPACITY - 1) + slot] = values[slot].trace;
+        for (u32 slot = 0; slot < CAPACITY; slot++) {
+            if (keys[slot] != 0 && loadAcquire(values[slot].counter) != 0) {
+                CallTrace* trace = values[slot].acquireTrace();
+                if (trace != NULL) {
+                    map[base + slot] = trace;
+                    // Reset to make sure each trace is dumped only once
+                    values[slot].setTrace(NULL);
+                }
             }
         }
     }
+
+    if (_overflow > 0) {
+        map[OVERFLOW_TRACE_ID] = &_overflow_trace;
+    }
 }
 
 void CallTraceStorage::collectSamples(std::vector<CallTraceSample*>& samples) {
     for (LongHashTable* table = _current_table; table != NULL; table = table->prev()) {
         u64* keys = table->keys();
         CallTraceSample* values = table->values();
-        u32 capacity = table->capacity();
 
-        for (u32 slot = 0; slot < capacity; slot++) {
+        for (u32 slot = 0; slot < CAPACITY; slot++) {
             if (keys[slot] != 0) {
                 samples.push_back(&values[slot]);
             }
@@ -133,6 +175,19 @@ void CallTraceStorage::collectSamples(std::vector<CallTraceSample*>& samples) {
     }
 }
 
+void CallTraceStorage::collectSamples(std::map<u64, CallTraceSample>& map) {
+    for (LongHashTable* table = _current_table; table != NULL; table = table->prev()) {
+        u64* keys = table->keys();
+        CallTraceSample* values = table->values();
+
+        for (u32 slot = 0; slot < CAPACITY; slot++) {
+            if (keys[slot] != 0 && values[slot].acquireTrace() != NULL) {
+                map[keys[slot]] += values[slot];
+            }
+        }
+    }
+}
+
 // Adaptation of MurmurHash64A by Austin Appleby
 u64 CallTraceStorage::calcHash(int num_frames, ASGCT_CallFrame* frames) {
     const u64 M = 0xc6a4a7935bd1e995ULL;
@@ -178,32 +233,12 @@ CallTrace* CallTraceStorage::storeCallTrace(int num_frames, ASGCT_CallFrame* fra
     return buf;
 }
 
-CallTrace* CallTraceStorage::findCallTrace(LongHashTable* table, u64 hash) {
-    u64* keys = table->keys();
-    u32 capacity = table->capacity();
-    u32 slot = hash & (capacity - 1);
-    u32 step = 0;
-
-    while (keys[slot] != hash) {
-        if (keys[slot] == 0) {
-            return NULL;
-        }
-        if (++step >= capacity) {
-            return NULL;
-        }
-        slot = (slot + step) & (capacity - 1);
-    }
-
-    return table->values()[slot].trace;
-}
-
 u32 CallTraceStorage::put(int num_frames, ASGCT_CallFrame* frames, u64 counter) {
     u64 hash = calcHash(num_frames, frames);
 
     LongHashTable* table = _current_table;
     u64* keys = table->keys();
-    u32 capacity = table->capacity();
-    u32 slot = hash & (capacity - 1);
+    u32 slot = hash & (CAPACITY - 1);
     u32 step = 0;
 
     while (keys[slot] != hash) {
@@ -213,34 +248,47 @@ u32 CallTraceStorage::put(int num_frames, ASGCT_CallFrame* frames, u64 counter)
             }
 
             // Increment the table size, and if the load factor exceeds 0.75, reserve a new table
-            if (table->incSize() == capacity * 3 / 4) {
-                LongHashTable* new_table = LongHashTable::allocate(table, capacity * 2);
+            if (table->incSize() == CAPACITY * 3 / 4) {
+                LongHashTable* new_table = LongHashTable::allocate(table, table->base() + CAPACITY);
                 if (new_table != NULL) {
                     __sync_bool_compare_and_swap(&_current_table, table, new_table);
                 }
             }
 
-            // Migrate from a previous table to save space
-            CallTrace* trace = table->prev() == NULL ? NULL : findCallTrace(table->prev(), hash);
-            if (trace == NULL) {
-                trace = storeCallTrace(num_frames, frames);
-            }
-            table->values()[slot].trace = trace;
+            CallTrace* trace = storeCallTrace(num_frames, frames);
+            table->values()[slot].setTrace(trace);
             break;
         }
 
-        if (++step >= capacity) {
+        if (++step >= CAPACITY) {
             // Very unlikely case of a table overflow
-            return 0;
+            atomicInc(_overflow);
+            return OVERFLOW_TRACE_ID;
         }
         // Improved version of linear probing
-        slot = (slot + step) & (capacity - 1);
+        slot = (slot + step) & (CAPACITY - 1);
     }
 
-    // TODO: check overhead
-    CallTraceSample& s = table->values()[slot];
-    atomicInc(s.samples);
-    atomicInc(s.counter, counter);
+    if (counter != 0) {
+        CallTraceSample& s = table->values()[slot];
+        atomicInc(s.samples);
+        atomicInc(s.counter, counter);
+    }
 
-    return capacity - (INITIAL_CAPACITY - 1) + slot;
+    return table->base() + slot;
+}
+
+void CallTraceStorage::add(u32 call_trace_id, u64 counter) {
+    if (call_trace_id == OVERFLOW_TRACE_ID) {
+        return;
+    }
+
+    for (LongHashTable* table = _current_table; table != NULL; table = table->prev()) {
+        if (call_trace_id >= table->base()) {
+            CallTraceSample& s = table->values()[call_trace_id - table->base()];
+            atomicInc(s.samples);
+            atomicInc(s.counter, counter);
+            break;
+        }
+    }
 }

src/callTraceStorage.h

@@ -35,26 +35,54 @@ struct CallTraceSample {
     CallTrace* trace;
     u64 samples;
     u64 counter;
+
+    CallTrace* acquireTrace() {
+        return __atomic_load_n(&trace, __ATOMIC_ACQUIRE);
+    }
+
+    void setTrace(CallTrace* value) {
+        return __atomic_store_n(&trace, value, __ATOMIC_RELEASE);
+    }
+
+    CallTraceSample& operator+=(const CallTraceSample& s) {
+        trace = s.trace;
+        samples += s.samples;
+        counter += s.counter;
+        return *this;
+    }
+
+    bool operator<(const CallTraceSample& other) const {
+        return counter > other.counter;
+    }
 };
 
 class CallTraceStorage {
   private:
+    static CallTrace _overflow_trace;
+
     LinearAllocator _allocator;
     LongHashTable* _current_table;
+    u64 _overflow;
 
     u64 calcHash(int num_frames, ASGCT_CallFrame* frames);
     CallTrace* storeCallTrace(int num_frames, ASGCT_CallFrame* frames);
-    CallTrace* findCallTrace(LongHashTable* table, u64 hash);
 
   public:
     CallTraceStorage();
     ~CallTraceStorage();
 
     void clear();
+    size_t usedMemory();
+    Chunk* trimAllocator();
+    LongHashTable* trimTable();
+    void freeMemory(Chunk* chunk, LongHashTable* table);
+
     void collectTraces(std::map<u32, CallTrace*>& map);
     void collectSamples(std::vector<CallTraceSample*>& samples);
+    void collectSamples(std::map<u64, CallTraceSample>& map);
 
     u32 put(int num_frames, ASGCT_CallFrame* frames, u64 counter);
+    void add(u32 call_trace_id, u64 counter);
 };
 
 #endif // _CALLTRACESTORAGE

src/codeCache.cpp

@@ -14,29 +14,78 @@
  * limitations under the License.
  */
 
+#include <stdint.h>
 #include <stdlib.h>
 #include <string.h>
+#include <sys/mman.h>
 #include "codeCache.h"
+#include "dwarf.h"
+#include "os.h"
 
 
+char* NativeFunc::create(const char* name, short lib_index) {
+    NativeFunc* f = (NativeFunc*)malloc(sizeof(NativeFunc) + 1 + strlen(name));
+    f->_lib_index = lib_index;
+    f->_mark = 0;
+    return strcpy(f->_name, name);
+}
+
+void NativeFunc::destroy(char* name) {
+    free(from(name));
+}
+
+size_t NativeFunc::usedMemory(const char* name) {
+    return sizeof(NativeFunc) + 1 + strlen(from(name)->_name);
+}
+
+
+CodeCache::CodeCache(const char* name, short lib_index, const void* min_address, const void* max_address) {
+    _name = NativeFunc::create(name, -1);
+    _lib_index = lib_index;
+    _min_address = min_address;
+    _max_address = max_address;
+    _text_base = NULL;
+
+    _got_start = NULL;
+    _got_end = NULL;
+    _got_patchable = false;
+    _debug_symbols = false;
+
+    _dwarf_table = NULL;
+    _dwarf_table_length = 0;
+
+    _capacity = INITIAL_CODE_CACHE_CAPACITY;
+    _count = 0;
+    _blobs = new CodeBlob[_capacity];
+}
+
+CodeCache::~CodeCache() {
+    for (int i = 0; i < _count; i++) {
+        NativeFunc::destroy(_blobs[i]._name);
+    }
+    NativeFunc::destroy(_name);
+    delete[] _blobs;
+    free(_dwarf_table);
+}
+
 void CodeCache::expand() {
     CodeBlob* old_blobs = _blobs;
     CodeBlob* new_blobs = new CodeBlob[_capacity * 2];
 
-    int live = 0;
-    for (int i = 0; i < _count; i++) {
-        if (_blobs[i]._method != NULL) {
-            new_blobs[live++] = _blobs[i];
-        }
-    }
+    memcpy(new_blobs, old_blobs, _count * sizeof(CodeBlob));
 
-    _count = live;
     _capacity *= 2;
     _blobs = new_blobs;
     delete[] old_blobs;
 }
 
-void CodeCache::add(const void* start, int length, jmethodID method, bool update_bounds) {
+void CodeCache::add(const void* start, int length, const char* name, bool update_bounds) {
+    char* name_copy = NativeFunc::create(name, _lib_index);
+    // Replace non-printable characters
+    for (char* s = name_copy; *s != 0; s++) {
+        if (*s < ' ') *s = '?';
+    }
+
     if (_count >= _capacity) {
         expand();
     }
@@ -44,58 +93,20 @@ void CodeCache::add(const void* start, int length, jmethodID method, bool update
     const void* end = (const char*)start + length;
     _blobs[_count]._start = start;
     _blobs[_count]._end = end;
-    _blobs[_count]._method = method;
+    _blobs[_count]._name = name_copy;
     _count++;
 
     if (update_bounds) {
-        if (start < _min_address) _min_address = start;
-        if (end > _max_address) _max_address = end;
+        updateBounds(start, end);
     }
 }
 
-void CodeCache::remove(const void* start, jmethodID method) {
-    for (int i = 0; i < _count; i++) {
-        if (_blobs[i]._start == start && _blobs[i]._method == method) {
-            _blobs[i]._method = NULL;
-            return;
-        }
-    }
+void CodeCache::updateBounds(const void* start, const void* end) {
+    if (start < _min_address) _min_address = start;
+    if (end > _max_address) _max_address = end;
 }
 
-jmethodID CodeCache::find(const void* address) {
-    for (int i = 0; i < _count; i++) {
-        CodeBlob* cb = _blobs + i;
-        if (address >= cb->_start && address < cb->_end && cb->_method != NULL) {
-            return _blobs[i]._method;
-        }
-    }
-    return NULL;
-}
-
-
-NativeCodeCache::NativeCodeCache(const char* name, const void* min_address, const void* max_address) {
-    _name = strdup(name);
-    _min_address = min_address;
-    _max_address = max_address;
-}
-
-NativeCodeCache::~NativeCodeCache() {
-    for (int i = 0; i < _count; i++) {
-        free(_blobs[i]._method);
-    }
-    free(_name);
-}
-
-void NativeCodeCache::add(const void* start, int length, const char* name, bool update_bounds) {
-    char* name_copy = strdup(name);
-    // Replace non-printable characters
-    for (char* s = name_copy; *s != 0; s++) {
-        if (*s < ' ') *s = '?';
-    }
-    CodeCache::add(start, length, (jmethodID)name_copy, update_bounds);
-}
-
-void NativeCodeCache::sort() {
+void CodeCache::sort() {
     if (_count == 0) return;
 
     qsort(_blobs, _count, sizeof(CodeBlob), CodeBlob::comparator);
@@ -104,7 +115,25 @@ void NativeCodeCache::sort() {
     if (_max_address == NO_MAX_ADDRESS) _max_address = _blobs[_count - 1]._end;
 }
 
-const char* NativeCodeCache::binarySearch(const void* address) {
+void CodeCache::mark(NamePredicate predicate) {
+    for (int i = 0; i < _count; i++) {
+        const char* blob_name = _blobs[i]._name;
+        if (blob_name != NULL && predicate(blob_name)) {
+            NativeFunc::mark(blob_name);
+        }
+    }
+}
+
+CodeBlob* CodeCache::find(const void* address) {
+    for (int i = 0; i < _count; i++) {
+        if (address >= _blobs[i]._start && address < _blobs[i]._end) {
+            return &_blobs[i];
+        }
+    }
+    return NULL;
+}
+
+const char* CodeCache::binarySearch(const void* address) {
     int low = 0;
     int high = _count - 1;
 
@@ -115,21 +144,21 @@ const char* NativeCodeCache::binarySearch(const void* address) {
         } else if (_blobs[mid]._start > address) {
             high = mid - 1;
         } else {
-            return (const char*)_blobs[mid]._method;
+            return _blobs[mid]._name;
         }
     }
 
     // Symbols with zero size can be valid functions: e.g. ASM entry points or kernel code.
     // Also, in some cases (endless loop) the return address may point beyond the function.
     if (low > 0 && (_blobs[low - 1]._start == _blobs[low - 1]._end || _blobs[low - 1]._end == address)) {
-        return (const char*)_blobs[low - 1]._method;
+        return _blobs[low - 1]._name;
     }
     return _name;
 }
 
-const void* NativeCodeCache::findSymbol(const char* name) {
+const void* CodeCache::findSymbol(const char* name) {
     for (int i = 0; i < _count; i++) {
-        const char* blob_name = (const char*)_blobs[i]._method;
+        const char* blob_name = _blobs[i]._name;
         if (blob_name != NULL && strcmp(blob_name, name) == 0) {
             return _blobs[i]._start;
         }
@@ -137,16 +166,86 @@ const void* NativeCodeCache::findSymbol(const char* name) {
     return NULL;
 }
 
-const void* NativeCodeCache::findSymbolByPrefix(const char* prefix) {
+const void* CodeCache::findSymbolByPrefix(const char* prefix) {
     return findSymbolByPrefix(prefix, strlen(prefix));
 }
 
-const void* NativeCodeCache::findSymbolByPrefix(const char* prefix, int prefix_len) {
+const void* CodeCache::findSymbolByPrefix(const char* prefix, int prefix_len) {
     for (int i = 0; i < _count; i++) {
-        const char* blob_name = (const char*)_blobs[i]._method;
+        const char* blob_name = _blobs[i]._name;
         if (blob_name != NULL && strncmp(blob_name, prefix, prefix_len) == 0) {
             return _blobs[i]._start;
         }
     }
     return NULL;
 }
+
+CodeBlob* CodeCache::findBlobByPrefix(const char* prefix) {
+    size_t prefix_len = strlen(prefix);
+    for (int i = 0; i < _count; i++) {
+        const char* blob_name = _blobs[i]._name;
+        if (blob_name != NULL && strncmp(blob_name, prefix, prefix_len) == 0) {
+            return &_blobs[i];
+        }
+    }
+    return NULL;
+}
+
+void CodeCache::setGlobalOffsetTable(void** start, void** end, bool patchable) {
+    _got_start = start;
+    _got_end = end;
+    _got_patchable = patchable;
+}
+
+void** CodeCache::findGlobalOffsetEntry(void* address) {
+    for (void** entry = _got_start; entry < _got_end; entry++) {
+        if (*entry == address) {
+            makeGotPatchable();
+            return entry;
+        }
+    }
+    return NULL;
+}
+
+void CodeCache::makeGotPatchable() {
+    if (!_got_patchable) {
+        uintptr_t got_start = (uintptr_t)_got_start & ~OS::page_mask;
+        uintptr_t got_size = ((uintptr_t)_got_end - got_start + OS::page_mask) & ~OS::page_mask;
+        mprotect((void*)got_start, got_size, PROT_READ | PROT_WRITE);
+        _got_patchable = true;
+    }
+}
+
+void CodeCache::setDwarfTable(FrameDesc* table, int length) {
+    _dwarf_table = table;
+    _dwarf_table_length = length;
+}
+
+FrameDesc* CodeCache::findFrameDesc(const void* pc) {
+    u32 target_loc = (const char*)pc - _text_base;
+    int low = 0;
+    int high = _dwarf_table_length - 1;
+
+    while (low <= high) {
+        int mid = (unsigned int)(low + high) >> 1;
+        if (_dwarf_table[mid].loc < target_loc) {
+            low = mid + 1;
+        } else if (_dwarf_table[mid].loc > target_loc) {
+            high = mid - 1;
+        } else {
+            return &_dwarf_table[mid];
+        }
+    }
+
+    return low > 0 ? &_dwarf_table[low - 1] : NULL;
+}
+
+size_t CodeCache::usedMemory() {
+    size_t bytes = _capacity * sizeof(CodeBlob);
+    bytes += _dwarf_table_length * sizeof(FrameDesc);
+    bytes += NativeFunc::usedMemory(_name);
+    for (int i = 0; i < _count; i++) {
+        bytes += NativeFunc::usedMemory(_blobs[i]._name);
+    }
+    return bytes;
+}

src/codeCache.h

@@ -23,14 +23,48 @@
 #define NO_MIN_ADDRESS  ((const void*)-1)
 #define NO_MAX_ADDRESS  ((const void*)0)
 
+typedef bool (*NamePredicate)(const char* name);
+
 const int INITIAL_CODE_CACHE_CAPACITY = 1000;
+const int MAX_NATIVE_LIBS = 2048;
+
+
+class NativeFunc {
+  private:
+    short _lib_index;
+    char _mark;
+    char _reserved;
+    char _name[0];
+
+    static NativeFunc* from(const char* name) {
+        return (NativeFunc*)(name - sizeof(NativeFunc));
+    }
+
+  public:
+    static char* create(const char* name, short lib_index);
+    static void destroy(char* name);
+
+    static size_t usedMemory(const char* name);
+
+    static short libIndex(const char* name) {
+        return from(name)->_lib_index;
+    }
+
+    static bool isMarked(const char* name) {
+        return from(name)->_mark != 0;
+    }
+
+    static void mark(const char* name) {
+        from(name)->_mark = 1;
+    }
+};
 
 
 class CodeBlob {
   public:
     const void* _start;
     const void* _end;
-    jmethodID _method;
+    char* _name;
 
     static int comparator(const void* c1, const void* c2) {
         CodeBlob* cb1 = (CodeBlob*)c1;
@@ -48,60 +82,119 @@ class CodeBlob {
 };
 
 
+class FrameDesc;
+
 class CodeCache {
   protected:
+    char* _name;
+    short _lib_index;
+    const void* _min_address;
+    const void* _max_address;
+    const char* _text_base;
+
+    void** _got_start;
+    void** _got_end;
+    bool _got_patchable;
+    bool _debug_symbols;
+
+    FrameDesc* _dwarf_table;
+    int _dwarf_table_length;
+
     int _capacity;
     int _count;
     CodeBlob* _blobs;
-    const void* _min_address;
-    const void* _max_address;
 
     void expand();
 
   public:
-    CodeCache() {
-        _capacity = INITIAL_CODE_CACHE_CAPACITY;
-        _count = 0;
-        _blobs = new CodeBlob[_capacity];
-        _min_address = NO_MIN_ADDRESS;
-        _max_address = NO_MAX_ADDRESS;
-    }
+    CodeCache(const char* name,
+              short lib_index = -1,
+              const void* min_address = NO_MIN_ADDRESS,
+              const void* max_address = NO_MAX_ADDRESS);
 
-    ~CodeCache() {
-        delete[] _blobs;
-    }
+    ~CodeCache();
 
-    bool contains(const void* address) {
-        return address >= _min_address && address < _max_address;
-    }
-
-    void add(const void* start, int length, jmethodID method, bool update_bounds = false);
-    void remove(const void* start, jmethodID method);
-    jmethodID find(const void* address);
-};
-
-
-class NativeCodeCache : public CodeCache {
-  private:
-    char* _name;
-
-  public:
-    NativeCodeCache(const char* name,
-                    const void* min_address = NO_MIN_ADDRESS,
-                    const void* max_address = NO_MAX_ADDRESS);
-
-    ~NativeCodeCache();
-
-    const char* name() {
+    const char* name() const {
         return _name;
     }
 
+    const void* minAddress() const {
+        return _min_address;
+    }
+
+    const void* maxAddress() const {
+        return _max_address;
+    }
+
+    bool contains(const void* address) const {
+        return address >= _min_address && address < _max_address;
+    }
+
+    void setTextBase(const char* text_base) {
+        _text_base = text_base;
+    }
+
+    void** gotStart() const {
+        return _got_start;
+    }
+
+    void** gotEnd() const {
+        return _got_end;
+    }
+
+    bool hasDebugSymbols() const {
+        return _debug_symbols;
+    }
+
+    void setDebugSymbols(bool debug_symbols) {
+        _debug_symbols = debug_symbols;
+    }
+
     void add(const void* start, int length, const char* name, bool update_bounds = false);
+    void updateBounds(const void* start, const void* end);
     void sort();
+    void mark(NamePredicate predicate);
+
+    CodeBlob* find(const void* address);
     const char* binarySearch(const void* address);
     const void* findSymbol(const char* name);
+    CodeBlob* findBlobByPrefix(const char* name);
     const void* findSymbolByPrefix(const char* prefix);
     const void* findSymbolByPrefix(const char* prefix, int prefix_len);
+
+    void setGlobalOffsetTable(void** start, void** end, bool patchable);
+    void** findGlobalOffsetEntry(void* address);
+    void makeGotPatchable();
+
+    void setDwarfTable(FrameDesc* table, int length);
+    FrameDesc* findFrameDesc(const void* pc);
+
+    size_t usedMemory();
+};
+
+
+class CodeCacheArray {
+  private:
+    CodeCache* _libs[MAX_NATIVE_LIBS];
+    int _count;
+
+  public:
+    CodeCacheArray() : _count(0) {
+    }
+
+    CodeCache* operator[](int index) {
+        return _libs[index];
+    }
+
+    int count() {
+        return __atomic_load_n(&_count, __ATOMIC_ACQUIRE);
+    }
+
+    void add(CodeCache* lib) {
+        int index = __atomic_load_n(&_count, __ATOMIC_ACQUIRE);
+        _libs[index] = lib;
+        __atomic_store_n(&_count, index + 1, __ATOMIC_RELEASE);
+    }
 };
 
 #endif // _CODECACHE_H

src/converter/Arguments.java

@@ -0,0 +1,106 @@
+/*
+ * Copyright 2022 Andrei Pangin
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import java.lang.reflect.Field;
+import java.lang.reflect.Modifier;
+import java.util.Calendar;
+import java.util.GregorianCalendar;
+import java.util.StringTokenizer;
+import java.util.regex.Pattern;
+
+class Arguments {
+    String title = "Flame Graph";
+    String highlight;
+    Pattern include;
+    Pattern exclude;
+    double minwidth;
+    int skip;
+    boolean reverse;
+    boolean cpu;
+    boolean alloc;
+    boolean live;
+    boolean lock;
+    boolean threads;
+    boolean total;
+    boolean lines;
+    boolean bci;
+    boolean simple;
+    boolean dot;
+    boolean collapsed;
+    long from;
+    long to;
+    String input;
+    String output;
+
+    Arguments(String... args) {
+        for (int i = 0; i < args.length; i++) {
+            String arg = args[i];
+            if (arg.startsWith("--")) {
+                try {
+                    Field f = Arguments.class.getDeclaredField(arg.substring(2));
+                    if ((f.getModifiers() & (Modifier.PRIVATE | Modifier.STATIC | Modifier.FINAL)) != 0) {
+                        throw new IllegalStateException(arg);
+                    }
+
+                    Class<?> type = f.getType();
+                    if (type == String.class) {
+                        f.set(this, args[++i]);
+                    } else if (type == boolean.class) {
+                        f.setBoolean(this, true);
+                    } else if (type == int.class) {
+                        f.setInt(this, Integer.parseInt(args[++i]));
+                    } else if (type == double.class) {
+                        f.setDouble(this, Double.parseDouble(args[++i]));
+                    } else if (type == long.class) {
+                        f.setLong(this, parseTimestamp(args[++i]));
+                    } else if (type == Pattern.class) {
+                        f.set(this, Pattern.compile(args[++i]));
+                    }
+                } catch (NoSuchFieldException | IllegalAccessException e) {
+                    throw new IllegalArgumentException(arg);
+                }
+            } else if (!arg.isEmpty()) {
+                if (input == null) {
+                    input = arg;
+                } else {
+                    output = arg;
+                }
+            }
+        }
+    }
+
+    // Milliseconds or HH:mm:ss.S or yyyy-MM-dd'T'HH:mm:ss.S
+    private long parseTimestamp(String time) {
+        if (time.indexOf(':') < 0) {
+            return Long.parseLong(time);
+        }
+
+        GregorianCalendar cal = new GregorianCalendar();
+        StringTokenizer st = new StringTokenizer(time, "-:.T");
+
+        if (time.indexOf('T') > 0) {
+            cal.set(Calendar.YEAR, Integer.parseInt(st.nextToken()));
+            cal.set(Calendar.MONTH, Integer.parseInt(st.nextToken()) - 1);
+            cal.set(Calendar.DAY_OF_MONTH, Integer.parseInt(st.nextToken()));
+        }
+        cal.set(Calendar.HOUR_OF_DAY, st.hasMoreTokens() ? Integer.parseInt(st.nextToken()) : 0);
+        cal.set(Calendar.MINUTE, st.hasMoreTokens() ? Integer.parseInt(st.nextToken()) : 0);
+        cal.set(Calendar.SECOND, st.hasMoreTokens() ? Integer.parseInt(st.nextToken()) : 0);
+        cal.set(Calendar.MILLISECOND, st.hasMoreTokens() ? Integer.parseInt(st.nextToken()) : 0);
+
+        return cal.getTimeInMillis();
+    }
+}

src/converter/CollapsedStacks.java

@@ -0,0 +1,50 @@
+/*
+ * Copyright 2022 Andrei Pangin
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import java.io.BufferedOutputStream;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.io.PrintStream;
+
+public class CollapsedStacks extends FlameGraph {
+    private final StringBuilder sb = new StringBuilder();
+    private final PrintStream out;
+
+    public CollapsedStacks(Arguments args) throws IOException {
+        super(args);
+        this.out = args.output == null ? System.out : new PrintStream(
+                new BufferedOutputStream(new FileOutputStream(args.output), 32768), false, "UTF-8");
+    }
+
+    @Override
+    public void addSample(String[] trace, long ticks) {
+        for (String s : trace) {
+            sb.append(s).append(';');
+        }
+        if (sb.length() > 0) sb.setCharAt(sb.length() - 1, ' ');
+        sb.append(ticks);
+
+        out.println(sb.toString());
+        sb.setLength(0);
+    }
+
+    @Override
+    public void dump() {
+        if (out != System.out) {
+            out.close();
+        }
+    }
+}

src/converter/FlameGraph.java

@@ -16,51 +16,43 @@
 
 import java.io.BufferedOutputStream;
 import java.io.BufferedReader;
+import java.io.ByteArrayOutputStream;
 import java.io.FileInputStream;
 import java.io.FileOutputStream;
 import java.io.IOException;
+import java.io.InputStream;
 import java.io.InputStreamReader;
 import java.io.PrintStream;
 import java.io.Reader;
 import java.nio.charset.StandardCharsets;
 import java.util.Map;
 import java.util.TreeMap;
+import java.util.regex.Pattern;
 
 public class FlameGraph {
-    public String title = "Flame Graph";
-    public boolean reverse;
-    public double minwidth;
-    public int skip;
-    public String input;
-    public String output;
+    public static final byte FRAME_INTERPRETED = 0;
+    public static final byte FRAME_JIT_COMPILED = 1;
+    public static final byte FRAME_INLINED = 2;
+    public static final byte FRAME_NATIVE = 3;
+    public static final byte FRAME_CPP = 4;
+    public static final byte FRAME_KERNEL = 5;
+    public static final byte FRAME_C1_COMPILED = 6;
 
-    private final Frame root = new Frame();
+    private final Arguments args;
+    private final Frame root = new Frame(FRAME_NATIVE);
     private int depth;
     private long mintotal;
 
+    public FlameGraph(Arguments args) {
+        this.args = args;
+    }
+
     public FlameGraph(String... args) {
-        for (int i = 0; i < args.length; i++) {
-            String arg = args[i];
-            if (!arg.startsWith("--") && !arg.isEmpty()) {
-                if (input == null) {
-                    input = arg;
-                } else {
-                    output = arg;
-                }
-            } else if (arg.equals("--title")) {
-                title = args[++i];
-            } else if (arg.equals("--reverse")) {
-                reverse = true;
-            } else if (arg.equals("--minwidth")) {
-                minwidth = Double.parseDouble(args[++i]);
-            } else if (arg.equals("--skip")) {
-                skip = Integer.parseInt(args[++i]);
-            }
-        }
+        this(new Arguments(args));
     }
 
     public void parse() throws IOException {
-        parse(new InputStreamReader(new FileInputStream(input), StandardCharsets.UTF_8));
+        parse(new InputStreamReader(new FileInputStream(args.input), StandardCharsets.UTF_8));
     }
 
     public void parse(Reader in) throws IOException {
@@ -77,29 +69,30 @@ public class FlameGraph {
     }
 
     public void addSample(String[] trace, long ticks) {
+        if (excludeTrace(trace)) {
+            return;
+        }
+
         Frame frame = root;
-        if (reverse) {
-            for (int i = trace.length; --i >= skip; ) {
-                frame.total += ticks;
-                frame = frame.child(trace[i]);
+        if (args.reverse) {
+            for (int i = trace.length; --i >= args.skip; ) {
+                frame = frame.addChild(trace[i], ticks);
             }
         } else {
-            for (int i = skip; i < trace.length; i++) {
-                frame.total += ticks;
-                frame = frame.child(trace[i]);
+            for (int i = args.skip; i < trace.length; i++) {
+                frame = frame.addChild(trace[i], ticks);
             }
         }
-        frame.total += ticks;
-        frame.self += ticks;
+        frame.addLeaf(ticks);
 
         depth = Math.max(depth, trace.length);
     }
 
     public void dump() throws IOException {
-        if (output == null) {
+        if (args.output == null) {
             dump(System.out);
         } else {
-            try (BufferedOutputStream bos = new BufferedOutputStream(new FileOutputStream(output), 32768);
+            try (BufferedOutputStream bos = new BufferedOutputStream(new FileOutputStream(args.output), 32768);
                  PrintStream out = new PrintStream(bos, false, "UTF-8")) {
                 dump(out);
             }
@@ -107,47 +100,51 @@ public class FlameGraph {
     }
 
     public void dump(PrintStream out) {
-        out.print(applyReplacements(HEADER,
-                "{title}", title,
-                "{height}", (depth + 1) * 16,
-                "{depth}", depth + 1,
-                "{reverse}", reverse));
+        mintotal = (long) (root.total * args.minwidth / 100);
+        int depth = mintotal > 1 ? root.depth(mintotal) : this.depth + 1;
+
+        String tail = getResource("/flame.html");
+
+        tail = printTill(out, tail, "/*height:*/300");
+        out.print(Math.min(depth * 16, 32767));
+
+        tail = printTill(out, tail, "/*title:*/");
+        out.print(args.title);
+
+        tail = printTill(out, tail, "/*reverse:*/false");
+        out.print(args.reverse);
+
+        tail = printTill(out, tail, "/*depth:*/0");
+        out.print(depth);
+
+        tail = printTill(out, tail, "/*frames:*/");
 
-        mintotal = (long) (root.total * minwidth / 100);
         printFrame(out, "all", root, 0, 0);
 
-        out.print(FOOTER);
+        tail = printTill(out, tail, "/*highlight:*/");
+        out.print(args.highlight != null ? "'" + escape(args.highlight) + "'" : "");
+
+        out.print(tail);
     }
 
-    // Replace ${variables} in the given string with field values
-    private String applyReplacements(String s, Object... params) {
-        StringBuilder result = new StringBuilder(s.length() + 256);
-
-        int p = 0;
-        for (int q; (q = s.indexOf('$', p)) >= 0; ) {
-            result.append(s, p, q);
-            p = s.indexOf('}', q + 2) + 1;
-            String var = s.substring(q + 1, p);
-            for (int i = 0; i < params.length; i += 2) {
-                if (var.equals(params[i])) {
-                    result.append(params[i + 1]);
-                    break;
-                }
-            }
-        }
-
-        result.append(s, p, s.length());
-        return result.toString();
+    private String printTill(PrintStream out, String data, String till) {
+        int index = data.indexOf(till);
+        out.print(data.substring(0, index));
+        return data.substring(index + till.length());
     }
 
     private void printFrame(PrintStream out, String title, Frame frame, int level, long x) {
-        int type = frameType(title);
-        title = stripSuffix(title);
-        if (title.indexOf('\'') >= 0) {
-            title = title.replace("'", "\\'");
+        int type = frame.getType();
+        if (type == FRAME_KERNEL) {
+            title = stripSuffix(title);
         }
 
-        out.println("f(" + level + "," + x + "," + frame.total + "," + type + ",'" + title + "')");
+        if ((frame.inlined | frame.c1 | frame.interpreted) != 0 && frame.inlined < frame.total && frame.interpreted < frame.total) {
+            out.println("f(" + level + "," + x + "," + frame.total + "," + type + ",'" + escape(title) + "'," +
+                    frame.inlined + "," + frame.c1 + "," + frame.interpreted + ")");
+        } else {
+            out.println("f(" + level + "," + x + "," + frame.total + "," + type + ",'" + escape(title) + "')");
+        }
 
         x += frame.self;
         for (Map.Entry<String, Frame> e : frame.entrySet()) {
@@ -159,33 +156,56 @@ public class FlameGraph {
         }
     }
 
-    private String stripSuffix(String title) {
-        int len = title.length();
-        if (len >= 4 && title.charAt(len - 1) == ']' && title.regionMatches(len - 4, "_[", 0, 2)) {
-            return title.substring(0, len - 4);
+    private boolean excludeTrace(String[] trace) {
+        Pattern include = args.include;
+        Pattern exclude = args.exclude;
+        if (include == null && exclude == null) {
+            return false;
         }
-        return title;
+
+        for (String frame : trace) {
+            if (exclude != null && exclude.matcher(frame).matches()) {
+                return true;
+            }
+            if (include != null && include.matcher(frame).matches()) {
+                include = null;
+                if (exclude == null) break;
+            }
+        }
+
+        return include != null;
     }
 
-    private int frameType(String title) {
-        if (title.endsWith("_[j]")) {
-            return 0;
-        } else if (title.endsWith("_[i]")) {
-            return 1;
-        } else if (title.endsWith("_[k]")) {
-            return 2;
-        } else if (title.contains("::") || title.startsWith("-[") || title.startsWith("+[")) {
-            return 3;
-        } else if (title.indexOf('/') > 0 || title.indexOf('.') > 0 && Character.isUpperCase(title.charAt(0))) {
-            return 0;
-        } else {
-            return 4;
+    static String stripSuffix(String title) {
+        return title.substring(0, title.length() - 4);
+    }
+
+    static String escape(String s) {
+        if (s.indexOf('\\') >= 0) s = s.replace("\\", "\\\\");
+        if (s.indexOf('\'') >= 0) s = s.replace("'", "\\'");
+        return s;
+    }
+
+    private static String getResource(String name) {
+        try (InputStream stream = FlameGraph.class.getResourceAsStream(name)) {
+            if (stream == null) {
+                throw new IOException("No resource found");
+            }
+
+            ByteArrayOutputStream result = new ByteArrayOutputStream();
+            byte[] buffer = new byte[64 * 1024];
+            for (int length; (length = stream.read(buffer)) != -1; ) {
+                result.write(buffer, 0, length);
+            }
+            return result.toString("UTF-8");
+        } catch (IOException e) {
+            throw new IllegalStateException("Can't load resource with name " + name);
         }
     }
 
-    public static void main(String[] args) throws IOException {
-        FlameGraph fg = new FlameGraph(args);
-        if (fg.input == null) {
+    public static void main(String[] cmdline) throws IOException {
+        Arguments args = new Arguments(cmdline);
+        if (args.input == null) {
             System.out.println("Usage: java " + FlameGraph.class.getName() + " [options] input.collapsed [output.html]");
             System.out.println();
             System.out.println("Options:");
@@ -193,250 +213,87 @@ public class FlameGraph {
             System.out.println("  --reverse");
             System.out.println("  --minwidth PERCENT");
             System.out.println("  --skip FRAMES");
+            System.out.println("  --include PATTERN");
+            System.out.println("  --exclude PATTERN");
+            System.out.println("  --highlight PATTERN");
             System.exit(1);
         }
 
+        FlameGraph fg = new FlameGraph(args);
         fg.parse();
         fg.dump();
     }
 
     static class Frame extends TreeMap<String, Frame> {
+        final byte type;
         long total;
         long self;
+        long inlined, c1, interpreted;
 
-        Frame child(String title) {
-            Frame child = get(title);
+        Frame(byte type) {
+            this.type = type;
+        }
+
+        byte getType() {
+            if (inlined * 3 >= total) {
+                return FRAME_INLINED;
+            } else if (c1 * 2 >= total) {
+                return FRAME_C1_COMPILED;
+            } else if (interpreted * 2 >= total) {
+                return FRAME_INTERPRETED;
+            } else {
+                return type;
+            }
+        }
+
+        private Frame getChild(String title, byte type) {
+            Frame child = super.get(title);
             if (child == null) {
-                put(title, child = new Frame());
+                super.put(title, child = new Frame(type));
             }
             return child;
         }
+
+        Frame addChild(String title, long ticks) {
+            total += ticks;
+
+            Frame child;
+            if (title.endsWith("_[j]")) {
+                child = getChild(stripSuffix(title), FRAME_JIT_COMPILED);
+            } else if (title.endsWith("_[i]")) {
+                (child = getChild(stripSuffix(title), FRAME_JIT_COMPILED)).inlined += ticks;
+            } else if (title.endsWith("_[k]")) {
+                child = getChild(title, FRAME_KERNEL);
+            } else if (title.endsWith("_[1]")) {
+                (child = getChild(stripSuffix(title), FRAME_JIT_COMPILED)).c1 += ticks;
+            } else if (title.endsWith("_[0]")) {
+                (child = getChild(stripSuffix(title), FRAME_JIT_COMPILED)).interpreted += ticks;
+            } else if (title.contains("::") || title.startsWith("-[") || title.startsWith("+[")) {
+                child = getChild(title, FRAME_CPP);
+            } else if (title.indexOf('/') > 0 && title.charAt(0) != '['
+                    || title.indexOf('.') > 0 && Character.isUpperCase(title.charAt(0))) {
+                child = getChild(title, FRAME_JIT_COMPILED);
+            } else {
+                child = getChild(title, FRAME_NATIVE);
+            }
+            return child;
+        }
+
+        void addLeaf(long ticks) {
+            total += ticks;
+            self += ticks;
+        }
+
+        int depth(long cutoff) {
+            int depth = 0;
+            if (size() > 0) {
+                for (Frame child : values()) {
+                    if (child.total >= cutoff) {
+                        depth = Math.max(depth, child.depth(cutoff));
+                    }
+                }
+            }
+            return depth + 1;
+        }
     }
-
-    private static final String HEADER = "<!DOCTYPE html>\n" +
-            "<html lang='en'>\n" +
-            "<head>\n" +
-            "<meta charset='utf-8'>\n" +
-            "<style>\n" +
-            "\tbody {margin: 0; padding: 10px; background-color: #ffffff}\n" +
-            "\th1 {margin: 5px 0 0 0; font-size: 18px; font-weight: normal; text-align: center}\n" +
-            "\theader {margin: -24px 0 5px 0; line-height: 24px}\n" +
-            "\tbutton {font: 12px sans-serif; cursor: pointer}\n" +
-            "\tp {margin: 5px 0 5px 0}\n" +
-            "\ta {color: #0366d6}\n" +
-            "\t#hl {position: absolute; display: none; overflow: hidden; white-space: nowrap; pointer-events: none; background-color: #ffffe0; outline: 1px solid #ffc000; height: 15px}\n" +
-            "\t#hl span {padding: 0 3px 0 3px}\n" +
-            "\t#status {overflow: hidden; white-space: nowrap}\n" +
-            "\t#match {overflow: hidden; white-space: nowrap; display: none; float: right; text-align: right}\n" +
-            "\t#reset {cursor: pointer}\n" +
-            "</style>\n" +
-            "</head>\n" +
-            "<body style='font: 12px Verdana, sans-serif'>\n" +
-            "<h1>${title}</h1>\n" +
-            "<header style='text-align: left'><button id='reverse' title='Reverse'>&#x1f53b;</button>&nbsp;&nbsp;<button id='search' title='Search'>&#x1f50d;</button></header>\n" +
-            "<header style='text-align: right'>Produced by <a href='https://github.com/jvm-profiling-tools/async-profiler'>async-profiler</a></header>\n" +
-            "<canvas id='canvas' style='width: 100%; height: ${height}px'></canvas>\n" +
-            "<div id='hl'><span></span></div>\n" +
-            "<p id='match'>Matched: <span id='matchval'></span> <span id='reset' title='Clear'>&#x274c;</span></p>\n" +
-            "<p id='status'>&nbsp;</p>\n" +
-            "<script>\n" +
-            "\t// Copyright 2020 Andrei Pangin\n" +
-            "\t// Licensed under the Apache License, Version 2.0.\n" +
-            "\t'use strict';\n" +
-            "\tvar root, rootLevel, px, pattern;\n" +
-            "\tvar reverse = ${reverse};\n" +
-            "\tconst levels = Array(${depth});\n" +
-            "\tfor (let h = 0; h < levels.length; h++) {\n" +
-            "\t\tlevels[h] = [];\n" +
-            "\t}\n" +
-            "\n" +
-            "\tconst canvas = document.getElementById('canvas');\n" +
-            "\tconst c = canvas.getContext('2d');\n" +
-            "\tconst hl = document.getElementById('hl');\n" +
-            "\tconst status = document.getElementById('status');\n" +
-            "\n" +
-            "\tconst canvasWidth = canvas.offsetWidth;\n" +
-            "\tconst canvasHeight = canvas.offsetHeight;\n" +
-            "\tcanvas.style.width = canvasWidth + 'px';\n" +
-            "\tcanvas.width = canvasWidth * (devicePixelRatio || 1);\n" +
-            "\tcanvas.height = canvasHeight * (devicePixelRatio || 1);\n" +
-            "\tif (devicePixelRatio) c.scale(devicePixelRatio, devicePixelRatio);\n" +
-            "\tc.font = document.body.style.font;\n" +
-            "\n" +
-            "\tconst palette = [\n" +
-            "\t\t[0x50e150, 30, 30, 30],\n" +
-            "\t\t[0x50bebe, 30, 30, 30],\n" +
-            "\t\t[0xe17d00, 30, 30,  0],\n" +
-            "\t\t[0xc8c83c, 30, 30, 10],\n" +
-            "\t\t[0xe15a5a, 30, 40, 40],\n" +
-            "\t];\n" +
-            "\n" +
-            "\tfunction getColor(p) {\n" +
-            "\t\tconst v = Math.random();\n" +
-            "\t\treturn '#' + (p[0] + ((p[1] * v) << 16 | (p[2] * v) << 8 | (p[3] * v))).toString(16);\n" +
-            "\t}\n" +
-            "\n" +
-            "\tfunction f(level, left, width, type, title) {\n" +
-            "\t\tlevels[level].push({left: left, width: width, color: getColor(palette[type]), title: title});\n" +
-            "\t}\n" +
-            "\n" +
-            "\tfunction samples(n) {\n" +
-            "\t\treturn n === 1 ? '1 sample' : n.toString().replace(/\\B(?=(\\d{3})+(?!\\d))/g, ',') + ' samples';\n" +
-            "\t}\n" +
-            "\n" +
-            "\tfunction pct(a, b) {\n" +
-            "\t\treturn a >= b ? '100' : (100 * a / b).toFixed(2);\n" +
-            "\t}\n" +
-            "\n" +
-            "\tfunction findFrame(frames, x) {\n" +
-            "\t\tlet left = 0;\n" +
-            "\t\tlet right = frames.length - 1;\n" +
-            "\n" +
-            "\t\twhile (left <= right) {\n" +
-            "\t\t\tconst mid = (left + right) >>> 1;\n" +
-            "\t\t\tconst f = frames[mid];\n" +
-            "\n" +
-            "\t\t\tif (f.left > x) {\n" +
-            "\t\t\t\tright = mid - 1;\n" +
-            "\t\t\t} else if (f.left + f.width <= x) {\n" +
-            "\t\t\t\tleft = mid + 1;\n" +
-            "\t\t\t} else {\n" +
-            "\t\t\t\treturn f;\n" +
-            "\t\t\t}\n" +
-            "\t\t}\n" +
-            "\n" +
-            "\t\tif (frames[left] && (frames[left].left - x) * px < 0.5) return frames[left];\n" +
-            "\t\tif (frames[right] && (x - (frames[right].left + frames[right].width)) * px < 0.5) return frames[right];\n" +
-            "\n" +
-            "\t\treturn null;\n" +
-            "\t}\n" +
-            "\n" +
-            "\tfunction search(r) {\n" +
-            "\t\tif (r && (r = prompt('Enter regexp to search:', '')) === null) {\n" +
-            "\t\t\treturn;\n" +
-            "\t\t}\n" +
-            "\n" +
-            "\t\tpattern = r ? RegExp(r) : undefined;\n" +
-            "\t\tconst matched = render(root, rootLevel);\n" +
-            "\t\tdocument.getElementById('matchval').textContent = pct(matched, root.width) + '%';\n" +
-            "\t\tdocument.getElementById('match').style.display = r ? 'inherit' : 'none';\n" +
-            "\t}\n" +
-            "\n" +
-            "\tfunction render(newRoot, newLevel) {\n" +
-            "\t\tif (root) {\n" +
-            "\t\t\tc.fillStyle = '#ffffff';\n" +
-            "\t\t\tc.fillRect(0, 0, canvasWidth, canvasHeight);\n" +
-            "\t\t}\n" +
-            "\n" +
-            "\t\troot = newRoot || levels[0][0];\n" +
-            "\t\trootLevel = newLevel || 0;\n" +
-            "\t\tpx = canvasWidth / root.width;\n" +
-            "\n" +
-            "\t\tconst x0 = root.left;\n" +
-            "\t\tconst x1 = x0 + root.width;\n" +
-            "\t\tconst marked = [];\n" +
-            "\n" +
-            "\t\tfunction mark(f) {\n" +
-            "\t\t\treturn marked[f.left] >= f.width || (marked[f.left] = f.width);\n" +
-            "\t\t}\n" +
-            "\n" +
-            "\t\tfunction totalMarked() {\n" +
-            "\t\t\tlet total = 0;\n" +
-            "\t\t\tlet left = 0;\n" +
-            "\t\t\tfor (let x in marked) {\n" +
-            "\t\t\t\tif (+x >= left) {\n" +
-            "\t\t\t\t\ttotal += marked[x];\n" +
-            "\t\t\t\t\tleft = +x + marked[x];\n" +
-            "\t\t\t\t}\n" +
-            "\t\t\t}\n" +
-            "\t\t\treturn total;\n" +
-            "\t\t}\n" +
-            "\n" +
-            "\t\tfunction drawFrame(f, y, alpha) {\n" +
-            "\t\t\tif (f.left < x1 && f.left + f.width > x0) {\n" +
-            "\t\t\t\tc.fillStyle = pattern && f.title.match(pattern) && mark(f) ? '#ee00ee' : f.color;\n" +
-            "\t\t\t\tc.fillRect((f.left - x0) * px, y, f.width * px, 15);\n" +
-            "\n" +
-            "\t\t\t\tif (f.width * px >= 21) {\n" +
-            "\t\t\t\t\tconst chars = Math.floor(f.width * px / 7);\n" +
-            "\t\t\t\t\tconst title = f.title.length <= chars ? f.title : f.title.substring(0, chars - 2) + '..';\n" +
-            "\t\t\t\t\tc.fillStyle = '#000000';\n" +
-            "\t\t\t\t\tc.fillText(title, Math.max(f.left - x0, 0) * px + 3, y + 12, f.width * px - 6);\n" +
-            "\t\t\t\t}\n" +
-            "\n" +
-            "\t\t\t\tif (alpha) {\n" +
-            "\t\t\t\t\tc.fillStyle = 'rgba(255, 255, 255, 0.5)';\n" +
-            "\t\t\t\t\tc.fillRect((f.left - x0) * px, y, f.width * px, 15);\n" +
-            "\t\t\t\t}\n" +
-            "\t\t\t}\n" +
-            "\t\t}\n" +
-            "\n" +
-            "\t\tfor (let h = 0; h < levels.length; h++) {\n" +
-            "\t\t\tconst y = reverse ? h * 16 : canvasHeight - (h + 1) * 16;\n" +
-            "\t\t\tconst frames = levels[h];\n" +
-            "\t\t\tfor (let i = 0; i < frames.length; i++) {\n" +
-            "\t\t\t\tdrawFrame(frames[i], y, h < rootLevel);\n" +
-            "\t\t\t}\n" +
-            "\t\t}\n" +
-            "\n" +
-            "\t\treturn totalMarked();\n" +
-            "\t}\n" +
-            "\n" +
-            "\tcanvas.onmousemove = function() {\n" +
-            "\t\tconst h = Math.floor((reverse ? event.offsetY : (canvasHeight - event.offsetY)) / 16);\n" +
-            "\t\tif (h >= 0 && h < levels.length) {\n" +
-            "\t\t\tconst f = findFrame(levels[h], event.offsetX / px + root.left);\n" +
-            "\t\t\tif (f) {\n" +
-            "\t\t\t\thl.style.left = (Math.max(f.left - root.left, 0) * px + canvas.offsetLeft) + 'px';\n" +
-            "\t\t\t\thl.style.width = (Math.min(f.width, root.width) * px) + 'px';\n" +
-            "\t\t\t\thl.style.top = ((reverse ? h * 16 : canvasHeight - (h + 1) * 16) + canvas.offsetTop) + 'px';\n" +
-            "\t\t\t\thl.firstChild.textContent = f.title;\n" +
-            "\t\t\t\thl.style.display = 'block';\n" +
-            "\t\t\t\tcanvas.title = f.title + '\\n(' + samples(f.width) + ', ' + pct(f.width, levels[0][0].width) + '%)';\n" +
-            "\t\t\t\tcanvas.style.cursor = 'pointer';\n" +
-            "\t\t\t\tcanvas.onclick = function() {\n" +
-            "\t\t\t\t\tif (f != root) {\n" +
-            "\t\t\t\t\t\trender(f, h);\n" +
-            "\t\t\t\t\t\tcanvas.onmousemove();\n" +
-            "\t\t\t\t\t}\n" +
-            "\t\t\t\t};\n" +
-            "\t\t\t\tstatus.textContent = 'Function: ' + canvas.title;\n" +
-            "\t\t\t\treturn;\n" +
-            "\t\t\t}\n" +
-            "\t\t}\n" +
-            "\t\tcanvas.onmouseout();\n" +
-            "\t}\n" +
-            "\n" +
-            "\tcanvas.onmouseout = function() {\n" +
-            "\t\thl.style.display = 'none';\n" +
-            "\t\tstatus.textContent = '\\xa0';\n" +
-            "\t\tcanvas.title = '';\n" +
-            "\t\tcanvas.style.cursor = '';\n" +
-            "\t\tcanvas.onclick = '';\n" +
-            "\t}\n" +
-            "\n" +
-            "\tdocument.getElementById('reverse').onclick = function() {\n" +
-            "\t\treverse = !reverse;\n" +
-            "\t\trender();\n" +
-            "\t}\n" +
-            "\n" +
-            "\tdocument.getElementById('search').onclick = function() {\n" +
-            "\t\tsearch(true);\n" +
-            "\t}\n" +
-            "\n" +
-            "\tdocument.getElementById('reset').onclick = function() {\n" +
-            "\t\tsearch(false);\n" +
-            "\t}\n" +
-            "\n" +
-            "\twindow.onkeydown = function() {\n" +
-            "\t\tif (event.ctrlKey && event.keyCode === 70) {\n" +
-            "\t\t\tevent.preventDefault();\n" +
-            "\t\t\tsearch(true);\n" +
-            "\t\t} else if (event.keyCode === 27) {\n" +
-            "\t\t\tsearch(false);\n" +
-            "\t\t}\n" +
-            "\t}\n";
-
-    private static final String FOOTER = "render();\n" +
-            "</script></body></html>\n";
 }

src/converter/MANIFEST.MF

@@ -1 +0,0 @@
-Main-Class: Main

src/converter/Main.java

@@ -24,8 +24,9 @@ public class Main {
         System.out.println("Usage: java -cp converter.jar <Converter> [options] <input> <output>");
         System.out.println();
         System.out.println("Available converters:");
-        System.out.println("  FlameGraph input.collapsed output.html");
-        System.out.println("  jfr2flame  input.jfr       output.html");
-        System.out.println("  jfr2nflx   input.jfr       output.nflx");
+        System.out.println("  FlameGraph  input.collapsed output.html");
+        System.out.println("  jfr2flame   input.jfr       output.html");
+        System.out.println("  jfr2nflx    input.jfr       output.nflx");
+        System.out.println("  jfr2pprof   input.jfr       output.pprof");
     }
 }

src/converter/jfr2flame.java

@@ -19,72 +19,243 @@ import one.jfr.Dictionary;
 import one.jfr.JfrReader;
 import one.jfr.MethodRef;
 import one.jfr.StackTrace;
+import one.jfr.event.*;
 
+import java.io.IOException;
 import java.nio.charset.StandardCharsets;
+import java.util.Map;
 
 /**
  * Converts .jfr output produced by async-profiler to HTML Flame Graph.
  */
 public class jfr2flame {
 
-    private static final int FRAME_KERNEL = 5;
+    private static final String[] FRAME_SUFFIX = {"_[0]", "_[j]", "_[i]", "", "", "_[k]", "_[1]"};
 
     private final JfrReader jfr;
+    private final Arguments args;
     private final Dictionary<String> methodNames = new Dictionary<>();
 
-    public jfr2flame(JfrReader jfr) {
+    public jfr2flame(JfrReader jfr, Arguments args) {
         this.jfr = jfr;
+        this.args = args;
     }
 
-    public void convert(final FlameGraph fg) {
-        // Don't use lambda for faster startup
-        jfr.stackTraces.forEach(new Dictionary.Visitor<StackTrace>() {
-            @Override
-            public void visit(long id, StackTrace stackTrace) {
-                long[] methods = stackTrace.methods;
-                byte[] types = stackTrace.types;
-                String[] trace = new String[methods.length];
-                for (int i = 0; i < methods.length; i++) {
-                    trace[trace.length - 1 - i] = getMethodName(methods[i], types[i]);
+    public void convert(final FlameGraph fg) throws IOException {
+        EventAggregator agg = new EventAggregator(args.threads, args.total);
+
+        Class<? extends Event> eventClass =
+                args.live ? LiveObject.class :
+                        args.alloc ? AllocationSample.class :
+                                args.lock ? ContendedLock.class : ExecutionSample.class;
+        int threadState = args.cpu ? getMapKey(jfr.threadStates, "STATE_RUNNABLE") : -1;
+
+        long startTicks = args.from != 0 ? toTicks(args.from) : Long.MIN_VALUE;
+        long endTicks = args.to != 0 ? toTicks(args.to) : Long.MAX_VALUE;
+
+        for (Event event; (event = jfr.readEvent(eventClass)) != null; ) {
+            if (event.time >= startTicks && event.time <= endTicks) {
+                if (threadState < 0 || ((ExecutionSample) event).threadState == threadState) {
+                    agg.collect(event);
+                }
+            }
+        }
+
+        final double ticksToNanos = 1e9 / jfr.ticksPerSec;
+        final boolean scale = args.total && eventClass == ContendedLock.class && ticksToNanos != 1.0;
+
+        // Don't use lambda for faster startup
+        agg.forEach(new EventAggregator.Visitor() {
+            @Override
+            public void visit(Event event, long value) {
+                StackTrace stackTrace = jfr.stackTraces.get(event.stackTraceId);
+                if (stackTrace != null) {
+                    Arguments args = jfr2flame.this.args;
+                    long[] methods = stackTrace.methods;
+                    byte[] types = stackTrace.types;
+                    int[] locations = stackTrace.locations;
+                    String classFrame = getClassFrame(event);
+                    String[] trace = new String[methods.length + (args.threads ? 1 : 0) + (classFrame != null ? 1 : 0)];
+                    if (args.threads) {
+                        trace[0] = getThreadFrame(event.tid);
+                    }
+                    int idx = trace.length;
+                    if (classFrame != null) {
+                        trace[--idx] = classFrame;
+                    }
+                    for (int i = 0; i < methods.length; i++) {
+                        String methodName = getMethodName(methods[i], types[i]);
+                        int location;
+                        if (args.lines && (location = locations[i] >>> 16) != 0) {
+                            methodName += ":" + location;
+                        } else if (args.bci && (location = locations[i] & 0xffff) != 0) {
+                            methodName += "@" + location;
+                        }
+                        trace[--idx] = methodName + FRAME_SUFFIX[types[i]];
+                    }
+                    fg.addSample(trace, scale ? (long) (value * ticksToNanos) : value);
                 }
-                fg.addSample(trace, stackTrace.samples);
             }
         });
     }
 
-    private String getMethodName(long methodId, int type) {
+    private String getThreadFrame(int tid) {
+        String threadName = jfr.threads.get(tid);
+        return threadName == null ? "[tid=" + tid + ']' : '[' + threadName + " tid=" + tid + ']';
+    }
+
+    private String getClassFrame(Event event) {
+        long classId;
+        String suffix;
+        if (event instanceof AllocationSample) {
+            classId = ((AllocationSample) event).classId;
+            suffix = ((AllocationSample) event).tlabSize == 0 ? "_[k]" : "_[i]";
+        } else if (event instanceof ContendedLock) {
+            classId = ((ContendedLock) event).classId;
+            suffix = "_[i]";
+        } else if (event instanceof LiveObject) {
+            classId = ((LiveObject) event).classId;
+            suffix = "_[i]";
+        } else {
+            return null;
+        }
+
+        ClassRef cls = jfr.classes.get(classId);
+        if (cls == null) {
+            return "null";
+        }
+        byte[] className = jfr.symbols.get(cls.name);
+
+        int arrayDepth = 0;
+        while (className[arrayDepth] == '[') {
+            arrayDepth++;
+        }
+
+        StringBuilder sb = new StringBuilder(toJavaClassName(className, arrayDepth, true));
+        while (arrayDepth-- > 0) {
+            sb.append("[]");
+        }
+        return sb.append(suffix).toString();
+    }
+
+    private String getMethodName(long methodId, byte methodType) {
         String result = methodNames.get(methodId);
         if (result != null) {
             return result;
         }
 
         MethodRef method = jfr.methods.get(methodId);
-        ClassRef cls = jfr.classes.get(method.cls);
-        byte[] className = jfr.symbols.get(cls.name);
-        byte[] methodName = jfr.symbols.get(method.name);
-
-        if (className == null || className.length == 0) {
-            String methodStr = new String(methodName, StandardCharsets.UTF_8);
-            result = type == FRAME_KERNEL ? methodStr + "_[k]" : methodStr;
+        if (method == null) {
+            result = "unknown";
         } else {
-            String classStr = new String(className, StandardCharsets.UTF_8);
-            String methodStr = new String(methodName, StandardCharsets.UTF_8);
-            result = classStr + '.' + methodStr + "_[j]";
+            ClassRef cls = jfr.classes.get(method.cls);
+            byte[] className = jfr.symbols.get(cls.name);
+            byte[] methodName = jfr.symbols.get(method.name);
+
+            if (className == null || className.length == 0 || isNativeFrame(methodType)) {
+                result = new String(methodName, StandardCharsets.UTF_8);
+            } else {
+                String classStr = toJavaClassName(className, 0, args.dot);
+                String methodStr = new String(methodName, StandardCharsets.UTF_8);
+                result = classStr + '.' + methodStr;
+            }
         }
 
         methodNames.put(methodId, result);
         return result;
     }
 
-    public static void main(String[] args) throws Exception {
-        FlameGraph fg = new FlameGraph(args);
-        if (fg.input == null) {
+    private boolean isNativeFrame(byte methodType) {
+        return methodType >= FlameGraph.FRAME_NATIVE && methodType <= FlameGraph.FRAME_KERNEL
+                && jfr.frameTypes.size() > FlameGraph.FRAME_NATIVE + 1;
+    }
+
+    private String toJavaClassName(byte[] symbol, int start, boolean dotted) {
+        int end = symbol.length;
+        if (start > 0) {
+            switch (symbol[start]) {
+                case 'B':
+                    return "byte";
+                case 'C':
+                    return "char";
+                case 'S':
+                    return "short";
+                case 'I':
+                    return "int";
+                case 'J':
+                    return "long";
+                case 'Z':
+                    return "boolean";
+                case 'F':
+                    return "float";
+                case 'D':
+                    return "double";
+                case 'L':
+                    start++;
+                    end--;
+            }
+        }
+
+        if (args.simple) {
+            for (int i = end - 2; i >= start; i--) {
+                if (symbol[i] == '/' && (symbol[i + 1] < '0' || symbol[i + 1] > '9')) {
+                    start = i + 1;
+                    break;
+                }
+            }
+        }
+
+        String s = new String(symbol, start, end - start, StandardCharsets.UTF_8);
+        return dotted ? s.replace('/', '.') : s;
+    }
+
+    // millis can be an absolute timestamp or an offset from the beginning/end of the recording
+    private long toTicks(long millis) {
+        long nanos = millis * 1_000_000;
+        if (millis < 0) {
+            nanos += jfr.endNanos;
+        } else if (millis < 1500000000000L) {
+            nanos += jfr.startNanos;
+        }
+        return jfr.nanosToTicks(nanos);
+    }
+
+    private static int getMapKey(Map<Integer, String> map, String value) {
+        for (Map.Entry<Integer, String> entry : map.entrySet()) {
+            if (value.equals(entry.getValue())) {
+                return entry.getKey();
+            }
+        }
+        return -1;
+    }
+
+    public static void main(String[] cmdline) throws Exception {
+        Arguments args = new Arguments(cmdline);
+        if (args.input == null) {
             System.out.println("Usage: java " + jfr2flame.class.getName() + " [options] input.jfr [output.html]");
+            System.out.println();
+            System.out.println("options include all supported FlameGraph options, plus the following:");
+            System.out.println("  --cpu        CPU Flame Graph");
+            System.out.println("  --alloc      Allocation Flame Graph");
+            System.out.println("  --live       Include only live objects in allocation profile");
+            System.out.println("  --lock       Lock contention Flame Graph");
+            System.out.println("  --threads    Split profile by threads");
+            System.out.println("  --total      Accumulate the total value (time, bytes, etc.)");
+            System.out.println("  --lines      Show line numbers");
+            System.out.println("  --bci        Show bytecode indices");
+            System.out.println("  --simple     Simple class names instead of FQN");
+            System.out.println("  --dot        Dotted class names");
+            System.out.println("  --from TIME  Start time in ms (absolute or relative)");
+            System.out.println("  --to TIME    End time in ms (absolute or relative)");
+            System.out.println("  --collapsed  Use collapsed stacks output format");
             System.exit(1);
         }
 
-        try (JfrReader jfr = new JfrReader(fg.input)) {
-            new jfr2flame(jfr).convert(fg);
+        boolean collapsed = args.collapsed || args.output != null && args.output.endsWith(".collapsed");
+        FlameGraph fg = collapsed ? new CollapsedStacks(args) : new FlameGraph(args);
+
+        try (JfrReader jfr = new JfrReader(args.input)) {
+            new jfr2flame(jfr, args).convert(fg);
         }
 
         fg.dump();

src/converter/jfr2nflx.java

@@ -15,11 +15,12 @@
  */
 
 import one.jfr.ClassRef;
-import one.jfr.Dictionary;
 import one.jfr.JfrReader;
 import one.jfr.MethodRef;
-import one.jfr.Sample;
 import one.jfr.StackTrace;
+import one.jfr.event.Event;
+import one.jfr.event.EventAggregator;
+import one.jfr.event.ExecutionSample;
 import one.proto.Proto;
 
 import java.io.File;
@@ -27,6 +28,7 @@ import java.io.FileOutputStream;
 import java.io.IOException;
 import java.io.OutputStream;
 import java.util.Arrays;
+import java.util.List;
 
 /**
  * Converts .jfr output produced by async-profiler to nflxprofile format
@@ -35,24 +37,27 @@ import java.util.Arrays;
  */
 public class jfr2nflx {
 
-    private static final String[] FRAME_TYPE = {"jit", "jit", "inlined", "user", "user", "kernel"};
+    private static final String[] FRAME_TYPE = {"jit", "jit", "inlined", "user", "user", "kernel", "jit"};
     private static final byte[] NO_STACK = "[no_stack]".getBytes();
+    private static final byte[] UNKNOWN = "[unknown]".getBytes();
 
     private final JfrReader jfr;
+    private final List<ExecutionSample> samples;
 
-    public jfr2nflx(JfrReader jfr) {
+    public jfr2nflx(JfrReader jfr) throws IOException {
         this.jfr = jfr;
+        this.samples = jfr.readAllEvents(ExecutionSample.class);
     }
 
     public void dump(OutputStream out) throws IOException {
         long startTime = System.nanoTime();
 
-        int samples = jfr.samples.size();
-        long durationTicks = samples == 0 ? 0 : jfr.samples.get(samples - 1).time - jfr.startTicks + 1;
+        int size = samples.size();
+        long durationTicks = size == 0 ? 0 : samples.get(size - 1).time - jfr.startTicks + 1;
 
         final Proto profile = new Proto(200000)
                 .field(1, 0.0)
-                .field(2, Math.max(jfr.durationNanos / 1e9, durationTicks / (double) jfr.ticksPerSec))
+                .field(2, Math.max(jfr.durationNanos() / 1e9, durationTicks / (double) jfr.ticksPerSec))
                 .field(3, packSamples())
                 .field(4, packDeltas())
                 .field(6, "async-profiler")
@@ -63,15 +68,23 @@ public class jfr2nflx {
         final Proto nodes = new Proto(10000);
         final Proto node = new Proto(10000);
 
+        EventAggregator agg = new EventAggregator(false, false);
+        for (ExecutionSample sample : samples) {
+            agg.collect(sample);
+        }
+
         // Don't use lambda for faster startup
-        jfr.stackTraces.forEach(new Dictionary.Visitor<StackTrace>() {
+        agg.forEach(new EventAggregator.Visitor() {
             @Override
-            public void visit(long id, StackTrace stackTrace) {
-                profile.field(5, nodes
-                        .field(1, (int) id)
-                        .field(2, packNode(node, stackTrace)));
-                nodes.reset();
-                node.reset();
+            public void visit(Event event, long value) {
+                StackTrace stackTrace = jfr.stackTraces.get(event.stackTraceId);
+                if (stackTrace != null) {
+                    profile.field(5, nodes
+                            .field(1, event.stackTraceId)
+                            .field(2, packNode(node, stackTrace)));
+                    nodes.reset();
+                    node.reset();
+                }
             }
         });
 
@@ -86,13 +99,13 @@ public class jfr2nflx {
         byte[] types = stackTrace.types;
         int top = methods.length - 1;
 
-        node.field(1, top >= 0 ? getMethodName(methods[top]) : NO_STACK);
+        node.field(1, top >= 0 ? getMethodName(methods[top], types[top]) : NO_STACK);
         node.field(2, 1);
         node.field(4, top >= 0 ? FRAME_TYPE[types[top]] : "user");
 
         for (Proto frame = new Proto(100); --top >= 0; frame.reset()) {
             node.field(10, frame
-                    .field(1, getMethodName(methods[top]))
+                    .field(1, getMethodName(methods[top], types[top]))
                     .field(2, FRAME_TYPE[types[top]]));
         }
 
@@ -101,7 +114,7 @@ public class jfr2nflx {
 
     private Proto packSamples() {
         Proto proto = new Proto(10000);
-        for (Sample sample : jfr.samples) {
+        for (ExecutionSample sample : samples) {
             proto.writeInt(sample.stackTraceId);
         }
         return proto;
@@ -111,7 +124,7 @@ public class jfr2nflx {
         Proto proto = new Proto(10000);
         double ticksPerSec = jfr.ticksPerSec;
         long prevTime = jfr.startTicks;
-        for (Sample sample : jfr.samples) {
+        for (ExecutionSample sample : samples) {
             proto.writeDouble((sample.time - prevTime) / ticksPerSec);
             prevTime = sample.time;
         }
@@ -120,19 +133,24 @@ public class jfr2nflx {
 
     private Proto packTids() {
         Proto proto = new Proto(10000);
-        for (Sample sample : jfr.samples) {
+        for (ExecutionSample sample : samples) {
             proto.writeInt(sample.tid);
         }
         return proto;
     }
 
-    private byte[] getMethodName(long methodId) {
+    private byte[] getMethodName(long methodId, byte methodType) {
         MethodRef method = jfr.methods.get(methodId);
+        if (method == null) {
+            return UNKNOWN;
+        }
+
         ClassRef cls = jfr.classes.get(method.cls);
         byte[] className = jfr.symbols.get(cls.name);
         byte[] methodName = jfr.symbols.get(method.name);
 
-        if (className == null || className.length == 0) {
+        if ((methodType >= FlameGraph.FRAME_NATIVE && methodType <= FlameGraph.FRAME_KERNEL)
+                || className == null || className.length == 0) {
             return methodName;
         } else {
             byte[] fullName = Arrays.copyOf(className, className.length + 1 + methodName.length);

src/converter/jfr2pprof.java

@@ -0,0 +1,227 @@
+/*
+ * Copyright 2022 Andrei Pangin
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import one.jfr.ClassRef;
+import one.jfr.Dictionary;
+import one.jfr.JfrReader;
+import one.jfr.MethodRef;
+import one.jfr.StackTrace;
+import one.jfr.event.ExecutionSample;
+import one.proto.Proto;
+
+import java.io.File;
+import java.io.FileOutputStream;
+import java.io.OutputStream;
+import java.nio.charset.StandardCharsets;
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+/**
+ * Convert a JFR file to pprof
+ * <p>
+ * Protobuf definition: https://github.com/google/pprof/blob/44fc4e887b6b0cfb196973bcdb1fab95f0b3a75b/proto/profile.proto
+ */
+public class jfr2pprof {
+
+    public static class Method {
+        final byte[] name;
+
+        public Method(final byte[] name) {
+            this.name = name;
+        }
+
+        @Override
+        public int hashCode() {
+            return Arrays.hashCode(name);
+        }
+
+        @Override
+        public boolean equals(final Object other) {
+            return other instanceof Method && Arrays.equals(name, ((Method) other).name);
+        }
+    }
+
+    public static final byte[] METHOD_UNKNOWN = "[unknown]".getBytes();
+
+    // Profile IDs
+    public static final int PROFILE_SAMPLE_TYPE = 1;
+    public static final int PROFILE_SAMPLE = 2;
+    public static final int PROFILE_LOCATION = 4;
+    public static final int PROFILE_FUNCTION = 5;
+    public static final int PROFILE_STRING_TABLE = 6;
+    public static final int PROFILE_TIME_NANOS = 9;
+    public static final int PROFILE_DURATION_NANOS = 10;
+    public static final int PROFILE_COMMENT = 13;
+    public static final int PROFILE_DEFAULT_SAMPLE_TYPE = 14;
+
+    // ValueType IDs
+    public static final int VALUETYPE_TYPE = 1;
+    public static final int VALUETYPE_UNIT = 2;
+
+    // Sample IDs
+    public static final int SAMPLE_LOCATION_ID = 1;
+    public static final int SAMPLE_VALUE = 2;
+
+    // Location IDs
+    public static final int LOCATION_ID = 1;
+    public static final int LOCATION_LINE = 4;
+
+    // Line IDs
+    public static final int LINE_FUNCTION_ID = 1;
+    public static final int LINE_LINE = 2;
+
+    // Function IDs
+    public static final int FUNCTION_ID = 1;
+    public static final int FUNCTION_NAME = 2;
+
+    private final JfrReader reader;
+
+    public jfr2pprof(final JfrReader reader) {
+        this.reader = reader;
+    }
+
+    // `Proto` instances are mutable, careful with reordering
+    public void dump(final OutputStream out) throws Exception {
+        // Mutable IDs, need to start at 1
+        int functionId = 1;
+        int locationId = 1;
+        int stringId = 1;
+
+        // Used to de-dupe
+        final Map<Method, Integer> functions = new HashMap<>();
+        final Map<Method, Integer> locations = new HashMap<>();
+
+        final Proto profile = new Proto(200_000)
+                .field(PROFILE_TIME_NANOS, reader.startNanos)
+                .field(PROFILE_DURATION_NANOS, reader.durationNanos())
+                .field(PROFILE_DEFAULT_SAMPLE_TYPE, 0L)
+                .field(PROFILE_STRING_TABLE, "".getBytes(StandardCharsets.UTF_8)) // "" needs to be index 0
+                .field(PROFILE_STRING_TABLE, "async-profiler".getBytes(StandardCharsets.UTF_8))
+                .field(PROFILE_COMMENT, stringId++);
+
+        final Proto sampleType = new Proto(100);
+
+        profile.field(PROFILE_STRING_TABLE, "cpu".getBytes(StandardCharsets.UTF_8));
+        sampleType.field(VALUETYPE_TYPE, stringId++);
+
+        profile.field(PROFILE_STRING_TABLE, "nanoseconds".getBytes(StandardCharsets.UTF_8));
+        sampleType.field(VALUETYPE_UNIT, stringId++);
+
+        profile.field(PROFILE_SAMPLE_TYPE, sampleType);
+
+        final List<ExecutionSample> jfrSamples = reader.readAllEvents(ExecutionSample.class);
+        final Dictionary<StackTrace> stackTraces = reader.stackTraces;
+        long previousTime = reader.startTicks; // Mutate this to keep track of time deltas
+
+        // Iterate over samples
+        for (final ExecutionSample jfrSample : jfrSamples) {
+            final StackTrace stackTrace = stackTraces.get(jfrSample.stackTraceId);
+            final long[] methods = stackTrace.methods;
+            final byte[] types = stackTrace.types;
+
+            final long nanosSinceLastSample = (jfrSample.time - previousTime) * 1_000_000_000 / reader.ticksPerSec;
+            final Proto sample = new Proto(1_000).field(SAMPLE_VALUE, nanosSinceLastSample);
+
+            for (int current = 0; current < methods.length; current++) {
+                final byte methodType = types[current];
+                final long methodIdentifier = methods[current];
+                final byte[] methodName = getMethodName(methodIdentifier, methodType);
+                final Method method = new Method(methodName);
+                final int line = stackTrace.locations[current] >>> 16;
+
+                final Integer methodId = functions.get(method);
+                if (null == methodId) {
+                    final int funcId = functionId++;
+                    profile.field(PROFILE_STRING_TABLE, methodName);
+                    final Proto function = new Proto(16)
+                        .field(FUNCTION_ID, funcId)
+                        .field(FUNCTION_NAME, stringId++);
+
+                    profile.field(PROFILE_FUNCTION, function);
+
+                    functions.put(method, funcId);
+                }
+
+                final Integer locaId = locations.get(method);
+                if (null == locaId) {
+                    final int locId = locationId++;
+                    final Proto locLine = new Proto(16).field(LINE_FUNCTION_ID, functions.get(method));
+                    if (line > 0) {
+                        locLine.field(LINE_LINE, line);
+                    }
+
+                    final Proto location = new Proto(16)
+                        .field(LOCATION_ID, locId)
+                        .field(LOCATION_LINE, locLine);
+
+                    profile.field(PROFILE_LOCATION, location);
+
+                    locations.put(method, locId);
+                }
+
+                sample.field(SAMPLE_LOCATION_ID, locations.get(method));
+            }
+
+            profile.field(PROFILE_SAMPLE, sample);
+
+            previousTime = jfrSample.time;
+        }
+
+        out.write(profile.buffer(), 0, profile.size());
+    }
+
+    private byte[] getMethodName(final long methodId, final byte methodType) {
+        final MethodRef ref = reader.methods.get(methodId);
+        if (null == ref) {
+            return METHOD_UNKNOWN;
+        }
+
+        final ClassRef classRef = reader.classes.get(ref.cls);
+        final byte[] className = reader.symbols.get(classRef.name);
+        final byte[] methodName = reader.symbols.get(ref.name);
+
+        if ((methodType >= FlameGraph.FRAME_NATIVE && methodType <= FlameGraph.FRAME_KERNEL) || className == null || className.length == 0) {
+            // Native method
+            return methodName;
+        } else {
+            // JVM method
+            final byte[] fullName = new byte[className.length + 1 + methodName.length];
+            System.arraycopy(className, 0, fullName, 0, className.length);
+            fullName[className.length] = '.';
+            System.arraycopy(methodName, 0, fullName, className.length + 1, methodName.length);
+            return fullName;
+        }
+    }
+
+    public static void main(String[] args) throws Exception {
+        if (args.length < 2) {
+            System.out.println("Usage: java " + jfr2pprof.class.getName() + " input.jfr output.pprof");
+            System.exit(1);
+        }
+
+        File dst = new File(args[1]);
+        if (dst.isDirectory()) {
+            dst = new File(dst, new File(args[0]).getName().replace(".jfr", ".pprof"));
+        }
+
+        try (final JfrReader jfr = new JfrReader(args[0]);
+             final FileOutputStream out = new FileOutputStream(dst)) {
+            new jfr2pprof(jfr).dump(out);
+        }
+    }
+}

src/converter/one/jfr/Dictionary.java

@@ -31,22 +31,32 @@ public class Dictionary<T> {
         this.values = new Object[INITIAL_CAPACITY];
     }
 
+    public void clear() {
+        keys = new long[INITIAL_CAPACITY];
+        values = new Object[INITIAL_CAPACITY];
+        size = 0;
+    }
+
     public void put(long key, T value) {
         if (key == 0) {
             throw new IllegalArgumentException("Zero key not allowed");
         }
 
-        if (++size * 2 > keys.length) {
-            resize(keys.length * 2);
-        }
-
         int mask = keys.length - 1;
         int i = hashCode(key) & mask;
-        while (keys[i] != 0 && keys[i] != key) {
+        while (keys[i] != 0) {
+            if (keys[i] == key) {
+                values[i] = value;
+                return;
+            }
             i = (i + 1) & mask;
         }
         keys[i] = key;
         values[i] = value;
+
+        if (++size * 2 > keys.length) {
+            resize(keys.length * 2);
+        }
     }
 
     @SuppressWarnings("unchecked")
@@ -69,9 +79,8 @@ public class Dictionary<T> {
     }
 
     public int preallocate(int count) {
-        int newSize = size + count;
-        if (newSize * 2 > keys.length) {
-            resize(Integer.highestOneBit(newSize * 4 - 1));
+        if (count * 2 > keys.length) {
+            resize(Integer.highestOneBit(count * 4 - 1));
         }
         return count;
     }
@@ -98,6 +107,7 @@ public class Dictionary<T> {
     }
 
     private static int hashCode(long key) {
+        key *= 0xc6a4a7935bd1e995L;
         return (int) (key ^ (key >>> 32));
     }
 

src/converter/one/jfr/JfrReader.java

@@ -16,9 +16,12 @@
 
 package one.jfr;
 
+import one.jfr.event.*;
+
 import java.io.Closeable;
 import java.io.IOException;
 import java.nio.ByteBuffer;
+import java.nio.ByteOrder;
 import java.nio.channels.FileChannel;
 import java.nio.charset.StandardCharsets;
 import java.nio.file.Paths;
@@ -33,17 +36,19 @@ import java.util.Map;
  * Parses JFR output produced by async-profiler.
  */
 public class JfrReader implements Closeable {
+    private static final int BUFFER_SIZE = 2 * 1024 * 1024;
     private static final int CHUNK_HEADER_SIZE = 68;
-    private static final int CPOOL_OFFSET = 16;
-    private static final int META_OFFSET = 24;
+    private static final int CHUNK_SIGNATURE = 0x464c5200;
 
     private final FileChannel ch;
-    private final ByteBuffer buf;
+    private ByteBuffer buf;
+    private long filePosition;
 
-    public final long startNanos;
-    public final long durationNanos;
-    public final long startTicks;
-    public final long ticksPerSec;
+    public boolean incomplete;
+    public long startNanos = Long.MAX_VALUE;
+    public long endNanos = Long.MIN_VALUE;
+    public long startTicks = Long.MAX_VALUE;
+    public long ticksPerSec;
 
     public final Dictionary<JfrClass> types = new Dictionary<>();
     public final Map<String, JfrClass> typesByName = new HashMap<>();
@@ -54,29 +59,38 @@ public class JfrReader implements Closeable {
     public final Dictionary<StackTrace> stackTraces = new Dictionary<>();
     public final Map<Integer, String> frameTypes = new HashMap<>();
     public final Map<Integer, String> threadStates = new HashMap<>();
-    public final List<Sample> samples = new ArrayList<>();
+    public final Map<String, String> settings = new HashMap<>();
+
+    private int executionSample;
+    private int nativeMethodSample;
+    private int allocationInNewTLAB;
+    private int allocationOutsideTLAB;
+    private int allocationSample;
+    private int liveObject;
+    private int monitorEnter;
+    private int threadPark;
+    private int activeSetting;
+    private boolean activeSettingHasStack;
 
     public JfrReader(String fileName) throws IOException {
         this.ch = FileChannel.open(Paths.get(fileName), StandardOpenOption.READ);
-        this.buf = ch.map(FileChannel.MapMode.READ_ONLY, 0, ch.size());
+        this.buf = ByteBuffer.allocateDirect(BUFFER_SIZE);
 
-        if (buf.getInt(0) != 0x464c5200) {
-            throw new IOException("Not a valid JFR file");
+        buf.flip();
+        ensureBytes(CHUNK_HEADER_SIZE);
+        if (!readChunk(0)) {
+            throw new IOException("Incomplete JFR file");
         }
+    }
 
-        int version = buf.getInt(4);
-        if (version < 0x20000 || version > 0x2ffff) {
-            throw new IOException("Unsupported JFR version: " + (version >>> 16) + "." + (version & 0xffff));
+    public JfrReader(ByteBuffer buf) throws IOException {
+        this.ch = null;
+        this.buf = buf;
+
+        buf.order(ByteOrder.BIG_ENDIAN);
+        if (!readChunk(0)) {
+            throw new IOException("Incomplete JFR file");
         }
-
-        this.startNanos = buf.getLong(32);
-        this.durationNanos = buf.getLong(40);
-        this.startTicks = buf.getLong(48);
-        this.ticksPerSec = buf.getLong(56);
-
-        readMeta();
-        readConstantPool();
-        readEvents();
     }
 
     @Override
@@ -84,9 +98,157 @@ public class JfrReader implements Closeable {
         ch.close();
     }
 
-    private void readMeta() {
-        buf.position(buf.getInt(META_OFFSET + 4));
-        getVarint();
+    public long durationNanos() {
+        return endNanos - startNanos;
+    }
+
+    public long nanosToTicks(long nanos) {
+        return (long) ((nanos - startNanos) * (ticksPerSec / 1e9)) + startTicks;
+    }
+
+    public List<Event> readAllEvents() throws IOException {
+        return readAllEvents(null);
+    }
+
+    public <E extends Event> List<E> readAllEvents(Class<E> cls) throws IOException {
+        ArrayList<E> events = new ArrayList<>();
+        for (E event; (event = readEvent(cls)) != null; ) {
+            events.add(event);
+        }
+        Collections.sort(events);
+        return events;
+    }
+
+    public Event readEvent() throws IOException {
+        return readEvent(null);
+    }
+
+    @SuppressWarnings("unchecked")
+    public <E extends Event> E readEvent(Class<E> cls) throws IOException {
+        while (ensureBytes(CHUNK_HEADER_SIZE)) {
+            int pos = buf.position();
+            int size = getVarint();
+            int type = getVarint();
+
+            if (type == 'L' && buf.getInt(pos) == CHUNK_SIGNATURE) {
+                if (readChunk(pos)) {
+                    continue;
+                }
+                break;
+            }
+
+            if (type == executionSample || type == nativeMethodSample) {
+                if (cls == null || cls == ExecutionSample.class) return (E) readExecutionSample();
+            } else if (type == allocationInNewTLAB) {
+                if (cls == null || cls == AllocationSample.class) return (E) readAllocationSample(true);
+            } else if (type == allocationOutsideTLAB || type == allocationSample) {
+                if (cls == null || cls == AllocationSample.class) return (E) readAllocationSample(false);
+            } else if (type == liveObject) {
+                if (cls == null || cls == LiveObject.class) return (E) readLiveObject();
+            } else if (type == monitorEnter) {
+                if (cls == null || cls == ContendedLock.class) return (E) readContendedLock(false);
+            } else if (type == threadPark) {
+                if (cls == null || cls == ContendedLock.class) return (E) readContendedLock(true);
+            } else if (type == activeSetting) {
+                readActiveSetting();
+            }
+
+            seek(filePosition + pos + size);
+        }
+        return null;
+    }
+
+    private ExecutionSample readExecutionSample() {
+        long time = getVarlong();
+        int tid = getVarint();
+        int stackTraceId = getVarint();
+        int threadState = getVarint();
+        return new ExecutionSample(time, tid, stackTraceId, threadState);
+    }
+
+    private AllocationSample readAllocationSample(boolean tlab) {
+        long time = getVarlong();
+        int tid = getVarint();
+        int stackTraceId = getVarint();
+        int classId = getVarint();
+        long allocationSize = getVarlong();
+        long tlabSize = tlab ? getVarlong() : 0;
+        return new AllocationSample(time, tid, stackTraceId, classId, allocationSize, tlabSize);
+    }
+
+    private LiveObject readLiveObject() {
+        long time = getVarlong();
+        int tid = getVarint();
+        int stackTraceId = getVarint();
+        int classId = getVarint();
+        long allocationSize = getVarlong();
+        long allocatimeTime = getVarlong();
+        return new LiveObject(time, tid, stackTraceId, classId, allocationSize, allocatimeTime);
+    }
+
+    private ContendedLock readContendedLock(boolean hasTimeout) {
+        long time = getVarlong();
+        long duration = getVarlong();
+        int tid = getVarint();
+        int stackTraceId = getVarint();
+        int classId = getVarint();
+        if (hasTimeout) getVarlong();
+        long until = getVarlong();
+        long address = getVarlong();
+        return new ContendedLock(time, tid, stackTraceId, duration, classId);
+    }
+
+    private void readActiveSetting() {
+        long time = getVarlong();
+        long duration = getVarlong();
+        int tid = getVarint();
+        if (activeSettingHasStack) getVarint();
+        long id = getVarlong();
+        String name = getString();
+        String value = getString();
+        settings.put(name, value);
+    }
+
+    private boolean readChunk(int pos) throws IOException {
+        if (pos + CHUNK_HEADER_SIZE > buf.limit() || buf.getInt(pos) != CHUNK_SIGNATURE) {
+            throw new IOException("Not a valid JFR file");
+        }
+
+        int version = buf.getInt(pos + 4);
+        if (version < 0x20000 || version > 0x2ffff) {
+            throw new IOException("Unsupported JFR version: " + (version >>> 16) + "." + (version & 0xffff));
+        }
+
+        long cpOffset = buf.getLong(pos + 16);
+        long metaOffset = buf.getLong(pos + 24);
+        if (cpOffset == 0 || metaOffset == 0) {
+            incomplete = true;
+            return false;
+        }
+
+        startNanos = Math.min(startNanos, buf.getLong(pos + 32));
+        endNanos = Math.max(endNanos, buf.getLong(pos + 32) + buf.getLong(pos + 40));
+        startTicks = Math.min(startTicks, buf.getLong(pos + 48));
+        ticksPerSec = buf.getLong(pos + 56);
+
+        types.clear();
+        typesByName.clear();
+
+        long chunkStart = filePosition + pos;
+        readMeta(chunkStart + metaOffset);
+        readConstantPool(chunkStart + cpOffset);
+        cacheEventTypes();
+
+        seek(chunkStart + CHUNK_HEADER_SIZE);
+        return true;
+    }
+
+    private void readMeta(long metaOffset) throws IOException {
+        seek(metaOffset);
+        ensureBytes(5);
+
+        int posBeforeSize = buf.position();
+        ensureBytes(getVarint() - (buf.position() - posBeforeSize));
         getVarint();
         getVarlong();
         getVarlong();
@@ -133,15 +295,18 @@ public class JfrReader implements Closeable {
         }
     }
 
-    private void readConstantPool() {
-        int offset = buf.getInt(CPOOL_OFFSET + 4);
-        while (true) {
-            buf.position(offset);
-            getVarint();
+    private void readConstantPool(long cpOffset) throws IOException {
+        long delta;
+        do {
+            seek(cpOffset);
+            ensureBytes(5);
+
+            int posBeforeSize = buf.position();
+            ensureBytes(getVarint() - (buf.position() - posBeforeSize));
             getVarint();
             getVarlong();
             getVarlong();
-            long delta = getVarlong();
+            delta = getVarlong();
             getVarint();
 
             int poolCount = getVarint();
@@ -149,12 +314,7 @@ public class JfrReader implements Closeable {
                 int type = getVarint();
                 readConstants(types.get(type));
             }
-
-            if (delta == 0) {
-                break;
-            }
-            offset += delta;
-        }
+        } while (delta != 0 && (cpOffset += delta) > 0);
     }
 
     private void readConstants(JfrClass type) {
@@ -163,10 +323,10 @@ public class JfrReader implements Closeable {
                 buf.position(buf.position() + (CHUNK_HEADER_SIZE + 3));
                 break;
             case "java.lang.Thread":
-                readThreads(type.field("group") != null);
+                readThreads(type.fields.size());
                 break;
             case "java.lang.Class":
-                readClasses(type.field("hidden") != null);
+                readClasses(type.fields.size());
                 break;
             case "jdk.types.Symbol":
                 readSymbols();
@@ -188,7 +348,7 @@ public class JfrReader implements Closeable {
         }
     }
 
-    private void readThreads(boolean hasGroup) {
+    private void readThreads(int fieldCount) {
         int count = threads.preallocate(getVarint());
         for (int i = 0; i < count; i++) {
             long id = getVarlong();
@@ -196,12 +356,12 @@ public class JfrReader implements Closeable {
             int osThreadId = getVarint();
             String javaName = getString();
             long javaThreadId = getVarlong();
-            if (hasGroup) getVarlong();
+            readFields(fieldCount - 4);
             threads.put(id, javaName != null ? javaName : osName);
         }
     }
 
-    private void readClasses(boolean hasHidden) {
+    private void readClasses(int fieldCount) {
         int count = classes.preallocate(getVarint());
         for (int i = 0; i < count; i++) {
             long id = getVarlong();
@@ -209,7 +369,7 @@ public class JfrReader implements Closeable {
             long name = getVarlong();
             long pkg = getVarlong();
             int modifiers = getVarint();
-            if (hasHidden) getVarint();
+            readFields(fieldCount - 4);
             classes.put(id, new ClassRef(name));
         }
     }
@@ -241,13 +401,15 @@ public class JfrReader implements Closeable {
         int depth = getVarint();
         long[] methods = new long[depth];
         byte[] types = new byte[depth];
+        int[] locations = new int[depth];
         for (int i = 0; i < depth; i++) {
             methods[i] = getVarlong();
             int line = getVarint();
             int bci = getVarint();
+            locations[i] = line << 16 | (bci & 0xffff);
             types[i] = buf.get();
         }
-        return new StackTrace(methods, types);
+        return new StackTrace(methods, types, locations);
     }
 
     private void readSymbols() {
@@ -294,36 +456,23 @@ public class JfrReader implements Closeable {
         }
     }
 
-    private void readEvents() {
-        int executionSample = getTypeId("jdk.ExecutionSample");
-        int nativeMethodSample = getTypeId("jdk.NativeMethodSample");
-
-        buf.position(CHUNK_HEADER_SIZE);
-        while (buf.hasRemaining()) {
-            int position = buf.position();
-            int size = getVarint();
-            int type = getVarint();
-            if (type == executionSample || type == nativeMethodSample) {
-                readExecutionSample();
-            } else {
-                buf.position(position + size);
-            }
+    private void readFields(int count) {
+        while (count-- > 0) {
+            getVarlong();
         }
-
-        Collections.sort(samples);
     }
 
-    private void readExecutionSample() {
-        long time = getVarlong();
-        int tid = getVarint();
-        int stackTraceId = getVarint();
-        int threadState = getVarint();
-        samples.add(new Sample(time, tid, stackTraceId, threadState));
-
-        StackTrace stackTrace = stackTraces.get(stackTraceId);
-        if (stackTrace != null) {
-            stackTrace.samples++;
-        }
+    private void cacheEventTypes() {
+        executionSample = getTypeId("jdk.ExecutionSample");
+        nativeMethodSample = getTypeId("jdk.NativeMethodSample");
+        allocationInNewTLAB = getTypeId("jdk.ObjectAllocationInNewTLAB");
+        allocationOutsideTLAB = getTypeId("jdk.ObjectAllocationOutsideTLAB");
+        allocationSample = getTypeId("jdk.ObjectAllocationSample");
+        liveObject = getTypeId("profiler.LiveObject");
+        monitorEnter = getTypeId("jdk.JavaMonitorEnter");
+        threadPark = getTypeId("jdk.ThreadPark");
+        activeSetting = getTypeId("jdk.ActiveSetting");
+        activeSettingHasStack = activeSetting >= 0 && typesByName.get("jdk.ActiveSetting").field("stackTrace") != null;
     }
 
     private int getTypeId(String typeName) {
@@ -381,4 +530,41 @@ public class JfrReader implements Closeable {
         buf.get(bytes);
         return bytes;
     }
+
+    private void seek(long pos) throws IOException {
+        long bufPosition = pos - filePosition;
+        if (bufPosition >= 0 && bufPosition <= buf.limit()) {
+            buf.position((int) bufPosition);
+        } else {
+            filePosition = pos;
+            ch.position(pos);
+            buf.rewind().flip();
+        }
+    }
+
+    private boolean ensureBytes(int needed) throws IOException {
+        if (buf.remaining() >= needed) {
+            return true;
+        }
+
+        if (ch == null) {
+            return false;
+        }
+
+        filePosition += buf.position();
+
+        if (buf.capacity() < needed) {
+            ByteBuffer newBuf = ByteBuffer.allocateDirect(needed);
+            newBuf.put(buf);
+            buf = newBuf;
+        } else {
+            buf.compact();
+        }
+
+        while (ch.read(buf) > 0 && buf.position() < needed) {
+            // keep reading
+        }
+        buf.flip();
+        return buf.limit() > 0;
+    }
 }

src/converter/one/jfr/StackTrace.java

@@ -19,10 +19,11 @@ package one.jfr;
 public class StackTrace {
     public final long[] methods;
     public final byte[] types;
-    public long samples;
+    public final int[] locations;
 
-    public StackTrace(long[] methods, byte[] types) {
+    public StackTrace(long[] methods, byte[] types, int[] locations) {
         this.methods = methods;
         this.types = types;
+        this.locations = locations;
     }
 }

src/converter/one/jfr/event/AllocationSample.java

@@ -0,0 +1,49 @@
+/*
+ * Copyright 2021 Andrei Pangin
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package one.jfr.event;
+
+public class AllocationSample extends Event {
+    public final int classId;
+    public final long allocationSize;
+    public final long tlabSize;
+
+    public AllocationSample(long time, int tid, int stackTraceId, int classId, long allocationSize, long tlabSize) {
+        super(time, tid, stackTraceId);
+        this.classId = classId;
+        this.allocationSize = allocationSize;
+        this.tlabSize = tlabSize;
+    }
+
+    @Override
+    public int hashCode() {
+        return classId * 127 + stackTraceId + (tlabSize == 0 ? 17 : 0);
+    }
+
+    @Override
+    public boolean sameGroup(Event o) {
+        if (o instanceof AllocationSample) {
+            AllocationSample a = (AllocationSample) o;
+            return classId == a.classId && (tlabSize == 0) == (a.tlabSize == 0);
+        }
+        return false;
+    }
+
+    @Override
+    public long value() {
+        return tlabSize != 0 ? tlabSize : allocationSize;
+    }
+}

src/converter/one/jfr/event/ContendedLock.java

@@ -0,0 +1,47 @@
+/*
+ * Copyright 2021 Andrei Pangin
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package one.jfr.event;
+
+public class ContendedLock extends Event {
+    public final long duration;
+    public final int classId;
+
+    public ContendedLock(long time, int tid, int stackTraceId, long duration, int classId) {
+        super(time, tid, stackTraceId);
+        this.duration = duration;
+        this.classId = classId;
+    }
+
+    @Override
+    public int hashCode() {
+        return classId * 127 + stackTraceId;
+    }
+
+    @Override
+    public boolean sameGroup(Event o) {
+        if (o instanceof ContendedLock) {
+            ContendedLock c = (ContendedLock) o;
+            return classId == c.classId;
+        }
+        return false;
+    }
+
+    @Override
+    public long value() {
+        return duration;
+    }
+}

src/converter/one/jfr/event/Event.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2020 Andrei Pangin
+ * Copyright 2021 Andrei Pangin
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -14,23 +14,34 @@
  * limitations under the License.
  */
 
-package one.jfr;
+package one.jfr.event;
 
-public class Sample implements Comparable<Sample> {
+public abstract class Event implements Comparable<Event> {
     public final long time;
     public final int tid;
     public final int stackTraceId;
-    public final int threadState;
 
-    public Sample(long time, int tid, int stackTraceId, int threadState) {
+    protected Event(long time, int tid, int stackTraceId) {
         this.time = time;
         this.tid = tid;
         this.stackTraceId = stackTraceId;
-        this.threadState = threadState;
     }
 
     @Override
-    public int compareTo(Sample o) {
+    public int compareTo(Event o) {
         return Long.compare(time, o.time);
     }
+
+    @Override
+    public int hashCode() {
+        return stackTraceId;
+    }
+
+    public boolean sameGroup(Event o) {
+        return getClass() == o.getClass();
+    }
+
+    public long value() {
+        return 1;
+    }
 }

src/converter/one/jfr/event/EventAggregator.java

@@ -0,0 +1,103 @@
+/*
+ * Copyright 2021 Andrei Pangin
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package one.jfr.event;
+
+public class EventAggregator {
+    private static final int INITIAL_CAPACITY = 1024;
+
+    private final boolean threads;
+    private final boolean total;
+    private Event[] keys;
+    private long[] values;
+    private int size;
+
+    public EventAggregator(boolean threads, boolean total) {
+        this.threads = threads;
+        this.total = total;
+        this.keys = new Event[INITIAL_CAPACITY];
+        this.values = new long[INITIAL_CAPACITY];
+    }
+
+    public void collect(Event e) {
+        int mask = keys.length - 1;
+        int i = hashCode(e) & mask;
+        while (keys[i] != null) {
+            if (sameGroup(keys[i], e)) {
+                values[i] += total ? e.value() : 1;
+                return;
+            }
+            i = (i + 1) & mask;
+        }
+
+        keys[i] = e;
+        values[i] = total ? e.value() : 1;
+
+        if (++size * 2 > keys.length) {
+            resize(keys.length * 2);
+        }
+    }
+
+    public long getValue(Event e) {
+        int mask = keys.length - 1;
+        int i = hashCode(e) & mask;
+        while (keys[i] != null && !sameGroup(keys[i], e)) {
+            i = (i + 1) & mask;
+        }
+        return values[i];
+    }
+
+    public void forEach(Visitor visitor) {
+        for (int i = 0; i < keys.length; i++) {
+            if (keys[i] != null) {
+                visitor.visit(keys[i], values[i]);
+            }
+        }
+    }
+
+    private int hashCode(Event e) {
+        return e.hashCode() + (threads ? e.tid * 31 : 0);
+    }
+
+    private boolean sameGroup(Event e1, Event e2) {
+        return e1.stackTraceId == e2.stackTraceId && (!threads || e1.tid == e2.tid) && e1.sameGroup(e2);
+    }
+
+    private void resize(int newCapacity) {
+        Event[] newKeys = new Event[newCapacity];
+        long[] newValues = new long[newCapacity];
+        int mask = newKeys.length - 1;
+
+        for (int i = 0; i < keys.length; i++) {
+            if (keys[i] != null) {
+                for (int j = hashCode(keys[i]) & mask; ; j = (j + 1) & mask) {
+                    if (newKeys[j] == null) {
+                        newKeys[j] = keys[i];
+                        newValues[j] = values[i];
+                        break;
+                    }
+                }
+            }
+        }
+
+        keys = newKeys;
+        values = newValues;
+    }
+
+    public interface Visitor {
+        void visit(Event event, long value);
+    }
+}

src/converter/one/jfr/event/ExecutionSample.java

@@ -0,0 +1,26 @@
+/*
+ * Copyright 2021 Andrei Pangin
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package one.jfr.event;
+
+public class ExecutionSample extends Event {
+    public final int threadState;
+
+    public ExecutionSample(long time, int tid, int stackTraceId, int threadState) {
+        super(time, tid, stackTraceId);
+        this.threadState = threadState;
+    }
+}

src/converter/one/jfr/event/LiveObject.java

@@ -0,0 +1,49 @@
+/*
+ * Copyright 2022 Andrei Pangin
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package one.jfr.event;
+
+public class LiveObject extends Event {
+    public final int classId;
+    public final long allocationSize;
+    public final long allocationTime;
+
+    public LiveObject(long time, int tid, int stackTraceId, int classId, long allocationSize, long allocationTime) {
+        super(time, tid, stackTraceId);
+        this.classId = classId;
+        this.allocationSize = allocationSize;
+        this.allocationTime = allocationTime;
+    }
+
+    @Override
+    public int hashCode() {
+        return classId * 127 + stackTraceId;
+    }
+
+    @Override
+    public boolean sameGroup(Event o) {
+        if (o instanceof LiveObject) {
+            LiveObject a = (LiveObject) o;
+            return classId == a.classId;
+        }
+        return false;
+    }
+
+    @Override
+    public long value() {
+        return allocationSize;
+    }
+}

src/converter/one/proto/Proto.java

@@ -48,6 +48,12 @@ public class Proto {
         return this;
     }
 
+    public Proto field(int index, long n) {
+        tag(index, 0);
+        writeLong(n);
+        return this;
+    }
+
     public Proto field(int index, double d) {
         tag(index, 1);
         writeDouble(d);
@@ -83,6 +89,17 @@ public class Proto {
         buf[pos++] = (byte) n;
     }
 
+    public void writeLong(long n) {
+        int length = n == 0 ? 1 : (70 - Long.numberOfLeadingZeros(n)) / 7;
+        ensureCapacity(length);
+
+        while (n > 0x7f) {
+            buf[pos++] = (byte) (0x80 | (n & 0x7f));
+            n >>>= 7;
+        }
+        buf[pos++] = (byte) n;
+    }
+
     public void writeDouble(double d) {
         ensureCapacity(8);
         long n = Double.doubleToRawLongBits(d);

src/demangle.cpp

@@ -0,0 +1,127 @@
+/*
+ * Copyright 2023 Andrei Pangin
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <cxxabi.h>
+#include <stdlib.h>
+#include <string.h>
+#include "demangle.h"
+
+
+char* Demangle::demangleCpp(const char* s) {
+    int status;
+    char* result = abi::__cxa_demangle(s, NULL, NULL, &status);
+    if (result == NULL && status == -2) {
+        // Strip compiler-specific suffix (e.g. ".part.123") and retry demangling
+        char buf[512];
+        const char* p = strchr(s, '.');
+        if (p != NULL && p - s < sizeof(buf)) {
+            memcpy(buf, s, p - s);
+            buf[p - s] = 0;
+            result = abi::__cxa_demangle(buf, NULL, NULL, &status);
+        }
+    }
+    return result;
+}
+
+char* Demangle::demangleRust(const char* s, const char* e) {
+    // Demangled symbol can be 1.5x longer than original, e.g. 1A1B1C -> A::B::C
+    char* result = (char*)malloc((e - s) * 3 / 2 + 1);
+    if (result == NULL) {
+        return NULL;
+    }
+
+    char* r = result;
+    char* tmp;
+
+    while (s < e) {
+        unsigned long len = strtoul(s, &tmp, 10);
+        const char* next = tmp + len;
+        if (len == 0 || next > e) {
+            break;
+        }
+
+        s = tmp;
+        if (s[0] == '_' && s[1] == '$') s++;
+
+        if (r > result) {
+            *r++ = ':';
+            *r++ = ':';
+        }
+
+        while (s < next) {
+            if (s[0] == '$') {
+                if (s[1] == 'L' && s[2] == 'T' && s[3] == '$') {
+                    *r++ = '<';
+                    s += 4;
+                } else if (s[1] == 'G' && s[2] == 'T' && s[3] == '$') {
+                    *r++ = '>';
+                    s += 4;
+                } else if (s[1] == 'L' && s[2] == 'P' && s[3] == '$') {
+                    *r++ = '(';
+                    s += 4;
+                } else if (s[1] == 'R' && s[2] == 'P' && s[3] == '$') {
+                    *r++ = ')';
+                    s += 4;
+                } else if (s[1] == 'S' && s[2] == 'P' && s[3] == '$') {
+                    *r++ = '@';
+                    s += 4;
+                } else if (s[1] == 'B' && s[2] == 'P' && s[3] == '$') {
+                    *r++ = '*';
+                    s += 4;
+                } else if (s[1] == 'R' && s[2] == 'F' && s[3] == '$') {
+                    *r++ = '&';
+                    s += 4;
+                } else if (s[1] == 'C' && s[2] == '$') {
+                    *r++ = ',';
+                    s += 3;
+                } else if (s[1] == 'u') {
+                    *r++ = (char)strtoul(s + 2, &tmp, 16);
+                    s = tmp + 1;
+                } else {
+                    *r++ = '$';
+                    s++;
+                }
+            } else if (s[0] == '.' && s[1] == '.') {
+                *r++ = ':';
+                *r++ = ':';
+                s += 2;
+            } else {
+                *r++ = *s++;
+            }
+        }
+
+        if (s > next) {
+            break;
+        }
+    }
+
+    *r = 0;
+    return result;
+}
+
+char* Demangle::demangle(const char* s) {
+    // Check if the mangled symbol ends with a Rust hash "17h<hex>E"
+    const char* e = strrchr(s, 'E');
+    if (e != NULL && e - s > 22 && e[-19] == '1' && e[-18] == '7' && e[-17] == 'h') {
+        const char* h = e - 16;
+        while ((*h >= '0' && *h <= '9') || (*h >= 'a' && *h <= 'f')) h++;
+        if (h == e) {
+            return demangleRust(s + 3, e - 19);
+        }
+    }
+
+    return demangleCpp(s);
+}

src/demangle.h

@@ -0,0 +1,30 @@
+/*
+ * Copyright 2023 Andrei Pangin
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef _DEMANGLE_H
+#define _DEMANGLE_H
+
+
+class Demangle {
+  private:
+    static char* demangleCpp(const char* s);
+    static char* demangleRust(const char* s, const char* e);
+
+  public:
+    static char* demangle(const char* s);
+};
+
+#endif // _DEMANGLE_H

src/dictionary.cpp

@@ -20,15 +20,16 @@
 #include "arch.h"
 
 
-static inline char* allocateKey(const char* key, size_t length) {
-    char* result = (char*)malloc(length + 1);
-    memcpy(result, key, length);
-    result[length] = 0;
-    return result;
+static inline DictKey* allocateKey(const char* key, size_t length) {
+    DictKey* dk = (DictKey*)malloc(length + 2);
+    dk->mark = false;
+    memcpy(dk->key, key, length);
+    dk->key[length] = 0;
+    return dk;
 }
 
-static inline bool keyEquals(const char* candidate, const char* key, size_t length) {
-    return strncmp(candidate, key, length) == 0 && candidate[length] == 0;
+static inline bool keyEquals(DictKey* dk, const char* key, size_t length) {
+    return strncmp(dk->key, key, length) == 0 && dk->key[length] == 0;
 }
 
 
@@ -61,6 +62,21 @@ void Dictionary::clear(DictTable* table) {
     }
 }
 
+size_t Dictionary::usedMemory() {
+    return _table != NULL ? usedMemory(_table) : 0;
+}
+
+size_t Dictionary::usedMemory(DictTable* table) {
+    size_t bytes = sizeof(DictTable);
+    for (int i = 0; i < ROWS; i++) {
+        DictRow* row = &table->rows[i];
+        if (row->next != NULL) {
+            bytes += usedMemory(row->next);
+        }
+    }
+    return bytes;
+}
+
 // Many popular symbols are quite short, e.g. "[B", "()V" etc.
 // FNV-1a is reasonably fast and sufficiently random.
 unsigned int Dictionary::hash(const char* key, size_t length) {
@@ -83,11 +99,11 @@ unsigned int Dictionary::lookup(const char* key, size_t length) {
         DictRow* row = &table->rows[h % ROWS];
         for (int c = 0; c < CELLS; c++) {
             if (row->keys[c] == NULL) {
-                char* new_key = allocateKey(key, length);
-                if (__sync_bool_compare_and_swap(&row->keys[c], NULL, new_key)) {
+                DictKey* new_dk = allocateKey(key, length);
+                if (__sync_bool_compare_and_swap(&row->keys[c], NULL, new_dk)) {
                     return table->index(h % ROWS, c);
                 }
-                free(new_key);
+                free(new_dk);
             }
             if (keyEquals(row->keys[c], key, length)) {
                 return table->index(h % ROWS, c);
@@ -115,8 +131,10 @@ void Dictionary::collect(std::map<unsigned int, const char*>& map, DictTable* ta
     for (int i = 0; i < ROWS; i++) {
         DictRow* row = &table->rows[i];
         for (int j = 0; j < CELLS; j++) {
-            if (row->keys[j] != NULL) {
-                map[table->index(i, j)] = row->keys[j];
+            DictKey* dk = row->keys[j];
+            if (dk != NULL && !dk->mark) {
+                dk->mark = true;
+                map[table->index(i, j)] = dk->key;
             }
         }
         if (row->next != NULL) {

src/dictionary.h

@@ -29,8 +29,13 @@
 
 struct DictTable;
 
+struct DictKey {
+    bool mark;
+    char key[0];
+};
+
 struct DictRow {
-    char* keys[CELLS];
+    DictKey* keys[CELLS];
     DictTable* next;
 };
 
@@ -50,6 +55,7 @@ class Dictionary {
     volatile unsigned int _base_index;
 
     static void clear(DictTable* table);
+    static size_t usedMemory(DictTable* table);
 
     static unsigned int hash(const char* key, size_t length);
 
@@ -60,6 +66,7 @@ class Dictionary {
     ~Dictionary();
 
     void clear();
+    size_t usedMemory();
 
     unsigned int lookup(const char* key);
     unsigned int lookup(const char* key, size_t length);

src/dwarf.cpp

@@ -0,0 +1,353 @@
+/*
+ * Copyright 2021 Andrei Pangin
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <stdlib.h>
+#include "dwarf.h"
+#include "log.h"
+
+
+enum {
+    DW_CFA_nop                = 0x0,
+    DW_CFA_set_loc            = 0x1,
+    DW_CFA_advance_loc1       = 0x2,
+    DW_CFA_advance_loc2       = 0x3,
+    DW_CFA_advance_loc4       = 0x4,
+    DW_CFA_offset_extended    = 0x5,
+    DW_CFA_restore_extended   = 0x6,
+    DW_CFA_undefined          = 0x7,
+    DW_CFA_same_value         = 0x8,
+    DW_CFA_register           = 0x9,
+    DW_CFA_remember_state     = 0xa,
+    DW_CFA_restore_state      = 0xb,
+    DW_CFA_def_cfa            = 0xc,
+    DW_CFA_def_cfa_register   = 0xd,
+    DW_CFA_def_cfa_offset     = 0xe,
+    DW_CFA_def_cfa_expression = 0xf,
+    DW_CFA_expression         = 0x10,
+    DW_CFA_offset_extended_sf = 0x11,
+    DW_CFA_def_cfa_sf         = 0x12,
+    DW_CFA_def_cfa_offset_sf  = 0x13,
+    DW_CFA_val_offset         = 0x14,
+    DW_CFA_val_offset_sf      = 0x15,
+    DW_CFA_val_expression     = 0x16,
+    DW_CFA_GNU_args_size      = 0x2e,
+
+    DW_CFA_advance_loc        = 0x1,
+    DW_CFA_offset             = 0x2,
+    DW_CFA_restore            = 0x3,
+};
+
+enum {
+    DW_OP_breg_pc = 0x70 + DW_REG_PC,
+    DW_OP_const1u = 0x08,
+    DW_OP_const1s = 0x09,
+    DW_OP_const2u = 0x0a,
+    DW_OP_const2s = 0x0b,
+    DW_OP_const4u = 0x0c,
+    DW_OP_const4s = 0x0d,
+    DW_OP_constu  = 0x10,
+    DW_OP_consts  = 0x11,
+    DW_OP_minus   = 0x1c,
+    DW_OP_plus    = 0x22,
+};
+
+
+FrameDesc FrameDesc::default_frame = {0, DW_REG_FP | (2 * DW_STACK_SLOT) << 8, -2 * DW_STACK_SLOT};
+
+
+DwarfParser::DwarfParser(const char* name, const char* image_base, const char* eh_frame_hdr) {
+    _name = name;
+    _image_base = image_base;
+
+    _capacity = 128;
+    _count = 0;
+    _table = (FrameDesc*)malloc(_capacity * sizeof(FrameDesc));
+    _prev = NULL;
+
+    _code_align = sizeof(instruction_t);
+    _data_align = -(int)sizeof(void*);
+
+    parse(eh_frame_hdr);
+}
+
+void DwarfParser::parse(const char* eh_frame_hdr) {
+    u8 version = eh_frame_hdr[0];
+    u8 eh_frame_ptr_enc = eh_frame_hdr[1];
+    u8 fde_count_enc = eh_frame_hdr[2];
+    u8 table_enc = eh_frame_hdr[3];
+
+    if (version != 1 || (eh_frame_ptr_enc & 0x7) != 0x3 || (fde_count_enc & 0x7) != 0x3 || (table_enc & 0xf7) != 0x33) {
+        Log::warn("Unsupported .eh_frame_hdr [%02x%02x%02x%02x] in %s",
+                  version, eh_frame_ptr_enc, fde_count_enc, table_enc, _name);
+        return;
+    }
+
+    int fde_count = *(int*)(eh_frame_hdr + 8);
+    int* table =  (int*)(eh_frame_hdr + 16);
+    for (int i = 0; i < fde_count; i++) {
+        _ptr = eh_frame_hdr + table[i * 2];
+        parseFde();
+    }
+}
+
+void DwarfParser::parseCie() {
+    u32 cie_len = get32();
+    if (cie_len == 0 || cie_len == 0xffffffff) {
+        return;
+    }
+
+    const char* cie_start = _ptr;
+    _ptr += 5;
+    while (*_ptr++) {}
+    _code_align = getLeb();
+    _data_align = getSLeb();
+    _ptr = cie_start + cie_len;
+}
+
+void DwarfParser::parseFde() {
+    u32 fde_len = get32();
+    if (fde_len == 0 || fde_len == 0xffffffff) {
+        return;
+    }
+
+    const char* fde_start = _ptr;
+    u32 cie_offset = get32();
+    if (_count == 0) {
+        _ptr = fde_start - cie_offset;
+        parseCie();
+        _ptr = fde_start + 4;
+    }
+
+    u32 range_start = getPtr() - _image_base;
+    u32 range_len = get32();
+    _ptr += getLeb();
+    parseInstructions(range_start, fde_start + fde_len);
+    addRecord(range_start + range_len, DW_REG_FP, 2 * DW_STACK_SLOT, -2 * DW_STACK_SLOT);
+}
+
+void DwarfParser::parseInstructions(u32 loc, const char* end) {
+    const u32 code_align = _code_align;
+    const int data_align = _data_align;
+
+    u32 cfa_reg = DW_REG_SP;
+    int cfa_off = DW_STACK_SLOT;
+    int fp_off = DW_SAME_FP;
+    int pc_off = -DW_STACK_SLOT;
+
+    u32 rem_cfa_reg;
+    int rem_cfa_off;
+    int rem_fp_off;
+    int rem_pc_off;
+
+    while (_ptr < end) {
+        u8 op = get8();
+        switch (op >> 6) {
+            case 0:
+                switch (op) {
+                    case DW_CFA_nop:
+                    case DW_CFA_set_loc:
+                        _ptr = end;
+                        break;
+                    case DW_CFA_advance_loc1:
+                        addRecord(loc, cfa_reg, cfa_off, fp_off);
+                        loc += get8() * code_align;
+                        break;
+                    case DW_CFA_advance_loc2:
+                        addRecord(loc, cfa_reg, cfa_off, fp_off);
+                        loc += get16() * code_align;
+                        break;
+                    case DW_CFA_advance_loc4:
+                        addRecord(loc, cfa_reg, cfa_off, fp_off);
+                        loc += get32() * code_align;
+                        break;
+                    case DW_CFA_offset_extended:
+                        switch (getLeb()) {
+                            case DW_REG_FP: fp_off = getLeb() * data_align; break;
+                            case DW_REG_PC: pc_off = getLeb() * data_align; break;
+                            default: skipLeb();
+                        }
+                        break;
+                    case DW_CFA_restore_extended:
+                    case DW_CFA_undefined:
+                    case DW_CFA_same_value:
+                        skipLeb();
+                        break;
+                    case DW_CFA_register:
+                        skipLeb();
+                        skipLeb();
+                        break;
+                    case DW_CFA_remember_state:
+                        rem_cfa_reg = cfa_reg;
+                        rem_cfa_off = cfa_off;
+                        rem_fp_off = fp_off;
+                        rem_pc_off = pc_off;
+                        break;
+                    case DW_CFA_restore_state:
+                        cfa_reg = rem_cfa_reg;
+                        cfa_off = rem_cfa_off;
+                        fp_off = rem_fp_off;
+                        pc_off = rem_pc_off;
+                        break;
+                    case DW_CFA_def_cfa:
+                        cfa_reg = getLeb();
+                        cfa_off = getLeb();
+                        break;
+                    case DW_CFA_def_cfa_register:
+                        cfa_reg = getLeb();
+                        break;
+                    case DW_CFA_def_cfa_offset:
+                        cfa_off = getLeb();
+                        break;
+                    case DW_CFA_def_cfa_expression: {
+                        u32 len = getLeb();
+                        cfa_reg = len == 11 ? DW_REG_PLT : DW_REG_INVALID;
+                        cfa_off = DW_STACK_SLOT;
+                        _ptr += len;
+                        break;
+                    }
+                    case DW_CFA_expression:
+                        skipLeb();
+                        _ptr += getLeb();
+                        break;
+                    case DW_CFA_offset_extended_sf:
+                        switch (getLeb()) {
+                            case DW_REG_FP: fp_off = getSLeb() * data_align; break;
+                            case DW_REG_PC: pc_off = getSLeb() * data_align; break;
+                            default: skipLeb();
+                        }
+                        break;
+                    case DW_CFA_def_cfa_sf:
+                        cfa_reg = getLeb();
+                        cfa_off = getSLeb() * data_align;
+                        break;
+                    case DW_CFA_def_cfa_offset_sf:
+                        cfa_off = getSLeb() * data_align;
+                        break;
+                    case DW_CFA_val_offset:
+                    case DW_CFA_val_offset_sf:
+                        skipLeb();
+                        skipLeb();
+                        break;
+                    case DW_CFA_val_expression:
+                        if (getLeb() == DW_REG_PC) {
+                            int pc_off = parseExpression();
+                            if (pc_off != 0) {
+                                fp_off = DW_PC_OFFSET | (pc_off << 1);
+                            }
+                        } else {
+                            _ptr += getLeb();
+                        }
+                        break;
+                    case DW_CFA_GNU_args_size:
+                        skipLeb();
+                        break;
+                    default:
+                        Log::warn("Unknown DWARF instruction 0x%x in %s", op, _name);
+                        return;
+                }
+                break;
+            case DW_CFA_advance_loc:
+                addRecord(loc, cfa_reg, cfa_off, fp_off);
+                loc += (op & 0x3f) * code_align;
+                break;
+            case DW_CFA_offset:
+                switch (op & 0x3f) {
+                    case DW_REG_FP: fp_off = getLeb() * data_align; break;
+                    case DW_REG_PC: pc_off = getLeb() * data_align; break;
+                    default: skipLeb();
+                }
+                break;
+            case DW_CFA_restore:
+                break;
+        }
+    }
+
+    addRecord(loc, cfa_reg, cfa_off, fp_off);
+}
+
+// Parse a limited subset of DWARF expressions, which is used in DW_CFA_val_expression
+// to point to the previous PC relative to the current PC.
+// Returns the offset of the previous PC from the current PC.
+int DwarfParser::parseExpression() {
+    int pc_off = 0;
+    int tos = 0;
+
+    u32 len = getLeb();
+    const char* end = _ptr + len;
+
+    while (_ptr < end) {
+        u8 op = get8();
+        switch (op) {
+            case DW_OP_breg_pc:
+                pc_off = getSLeb();
+                break;
+            case DW_OP_const1u:
+                tos = get8();
+                break;
+            case DW_OP_const1s:
+                tos = (signed char)get8();
+                break;
+            case DW_OP_const2u:
+                tos = get16();
+                break;
+            case DW_OP_const2s:
+                tos = (short)get16();
+                break;
+            case DW_OP_const4u:
+            case DW_OP_const4s:
+                tos = get32();
+                break;
+            case DW_OP_constu:
+                tos = getLeb();
+                break;
+            case DW_OP_consts:
+                tos = getSLeb();
+                break;
+            case DW_OP_minus:
+                pc_off -= tos;
+                break;
+            case DW_OP_plus:
+                pc_off += tos;
+                break;
+            default:
+                Log::warn("Unknown DWARF opcode 0x%x in %s", op, _name);
+                _ptr = end;
+                return 0;
+        }
+    }
+
+    return pc_off;
+}
+
+void DwarfParser::addRecord(u32 loc, u32 cfa_reg, int cfa_off, int fp_off) {
+    int cfa = cfa_reg | cfa_off << 8;
+    if (_prev == NULL || (_prev->loc == loc && --_count >= 0) || _prev->cfa != cfa || _prev->fp_off != fp_off) {
+        _prev = addRecordRaw(loc, cfa, fp_off);
+    }
+}
+
+FrameDesc* DwarfParser::addRecordRaw(u32 loc, int cfa, int fp_off) {
+    if (_count >= _capacity) {
+        _capacity *= 2;
+        _table = (FrameDesc*)realloc(_table, _capacity * sizeof(FrameDesc));
+    }
+
+    FrameDesc* f = &_table[_count++];
+    f->loc = loc;
+    f->cfa = cfa;
+    f->fp_off = fp_off;
+    return f;
+}

src/dwarf.h

@@ -0,0 +1,160 @@
+/*
+ * Copyright 2021 Andrei Pangin
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef _DWARF_H
+#define _DWARF_H
+
+#include <stddef.h>
+#include "arch.h"
+
+
+#if defined(__x86_64__)
+
+#define DWARF_SUPPORTED true
+
+const int DW_REG_FP = 6;
+const int DW_REG_SP = 7;
+const int DW_REG_PC = 16;
+
+#elif defined(__i386__)
+
+#define DWARF_SUPPORTED true
+
+const int DW_REG_FP = 5;
+const int DW_REG_SP = 4;
+const int DW_REG_PC = 8;
+
+#else
+
+#define DWARF_SUPPORTED false
+
+const int DW_REG_FP = 0;
+const int DW_REG_SP = 1;
+const int DW_REG_PC = 2;
+
+#endif
+
+const int DW_REG_PLT = 128;      // denotes special rule for PLT entries
+const int DW_REG_INVALID = 255;  // denotes unsupported configuration
+
+const int DW_PC_OFFSET = 1;
+const int DW_SAME_FP = 0x80000000;
+const int DW_STACK_SLOT = sizeof(void*);
+
+
+struct FrameDesc {
+    u32 loc;
+    int cfa;
+    int fp_off;
+
+    static FrameDesc default_frame;
+
+    static int comparator(const void* p1, const void* p2) {
+        FrameDesc* fd1 = (FrameDesc*)p1;
+        FrameDesc* fd2 = (FrameDesc*)p2;
+        return (int)(fd1->loc - fd2->loc);
+    }
+};
+
+
+class DwarfParser {
+  private:
+    const char* _name;
+    const char* _image_base;
+    const char* _ptr;
+
+    int _capacity;
+    int _count;
+    FrameDesc* _table;
+    FrameDesc* _prev;
+
+    u32 _code_align;
+    int _data_align;
+
+    const char* add(size_t size) {
+        const char* ptr = _ptr;
+        _ptr = ptr + size;
+        return ptr;
+    }
+
+    u8 get8() {
+        return *_ptr++;
+    }
+
+    u16 get16() {
+        return *(u16*)add(2);
+    }
+
+    u32 get32() {
+        return *(u32*)add(4);
+    }
+
+    u32 getLeb() {
+        u32 result = 0;
+        for (u32 shift = 0; ; shift += 7) {
+            u8 b = *_ptr++;
+            result |= (b & 0x7f) << shift;
+            if ((b & 0x80) == 0) {
+                return result;
+            }
+        }
+    }
+
+    int getSLeb() {
+        int result = 0;
+        for (u32 shift = 0; ; shift += 7) {
+            u8 b = *_ptr++;
+            result |= (b & 0x7f) << shift;
+            if ((b & 0x80) == 0) {
+                if ((b & 0x40) != 0 && (shift += 7) < 32) {
+                    result |= -1 << shift;
+                }
+                return result;
+            }
+        }
+    }
+
+    void skipLeb() {
+        while (*_ptr++ & 0x80) {}
+    }
+
+    const char* getPtr() {
+        const char* ptr = _ptr;
+        return ptr + *(int*)add(4);
+    }
+
+    void parse(const char* eh_frame_hdr);
+    void parseCie();
+    void parseFde();
+    void parseInstructions(u32 loc, const char* end);
+    int parseExpression();
+
+    void addRecord(u32 loc, u32 cfa_reg, int cfa_off, int fp_off);
+    FrameDesc* addRecordRaw(u32 loc, int cfa, int fp_off);
+
+  public:
+    DwarfParser(const char* name, const char* image_base, const char* eh_frame_hdr);
+
+    FrameDesc* table() const {
+        return _table;
+    }
+
+    int count() const {
+        return _count;
+    }
+};
+
+#endif // _DWARF_H

src/engine.cpp

@@ -15,60 +15,17 @@
  */
 
 #include "engine.h"
-#include "stackFrame.h"
 
 
-volatile bool Engine::_enabled;
+volatile bool Engine::_enabled = false;
 
 Error Engine::check(Arguments& args) {
     return Error::OK;
 }
 
-CStack Engine::cstack() {
-    return CSTACK_FP;
+Error Engine::start(Arguments& args) {
+    return Error::OK;
 }
 
-int Engine::getNativeTrace(void* ucontext, int tid, const void** callchain, int max_depth,
-                           CodeCache* java_methods, CodeCache* runtime_stubs) {
-    const void* pc;
-    uintptr_t fp;
-    uintptr_t prev_fp = (uintptr_t)&fp;
-    uintptr_t bottom = prev_fp + 0x100000;
-
-    if (ucontext == NULL) {
-        pc = __builtin_return_address(0);
-        fp = (uintptr_t)__builtin_frame_address(1);
-    } else {
-        StackFrame frame(ucontext);
-        pc = (const void*)frame.pc();
-        fp = frame.fp();
-    }
-
-    int depth = 0;
-    const void* const valid_pc = (const void* const)0x1000;
-
-    // Walk until the bottom of the stack or until the first Java frame
-    while (depth < max_depth && pc >= valid_pc) {
-        if (java_methods->contains(pc) || runtime_stubs->contains(pc)) {
-            break;
-        }
-
-        callchain[depth++] = pc;
-
-        // Check if the next frame is below on the current stack
-        if (fp <= prev_fp || fp >= prev_fp + 0x40000 || fp >= bottom) {
-            break;
-        }
-
-        // Frame pointer must be word aligned
-        if ((fp & (sizeof(uintptr_t) - 1)) != 0) {
-            break;
-        }
-
-        prev_fp = fp;
-        pc = ((const void**)fp)[1];
-        fp = ((uintptr_t*)fp)[0];
-    }
-
-    return depth;
+void Engine::stop() {
 }

src/engine.h

@@ -18,50 +18,50 @@
 #define _ENGINE_H
 
 #include "arguments.h"
-#include "codeCache.h"
 
 
+struct StackContext;
+
 class Engine {
   protected:
     static volatile bool _enabled;
 
+    static bool updateCounter(volatile unsigned long long& counter, unsigned long long value, unsigned long long interval) {
+        if (interval <= 1) {
+            return true;
+        }
+
+        while (true) {
+            unsigned long long prev = counter;
+            unsigned long long next = prev + value;
+            if (next < interval) {
+                if (__sync_bool_compare_and_swap(&counter, prev, next)) {
+                    return false;
+                }
+            } else {
+                if (__sync_bool_compare_and_swap(&counter, prev, next % interval)) {
+                    return true;
+                }
+            }
+        }
+    }
+
   public:
-    virtual const char* name() = 0;
-    virtual const char* units() = 0;
+    virtual const char* title() {
+        return "Flame Graph";
+    }
+
+    virtual const char* units() {
+        return "total";
+    }
 
     virtual Error check(Arguments& args);
-    virtual Error start(Arguments& args) = 0;
-    virtual void stop() = 0;
-
-    virtual CStack cstack();
-    virtual int getNativeTrace(void* ucontext, int tid, const void** callchain, int max_depth,
-                               CodeCache* java_methods, CodeCache* runtime_stubs);
+    virtual Error start(Arguments& args);
+    virtual void stop();
 
     void enableEvents(bool enabled) {
         _enabled = enabled;
     }
 };
 
-class NoopEngine : public Engine {
-  public:
-    const char* name() {
-        return "noop";
-    }
-
-    const char* units() {
-        return "ns";
-    }
-
-    Error start(Arguments& args) {
-        return Error::OK;
-    }
-
-    void stop() {
-    }
-
-    CStack cstack() {
-        return CSTACK_NO;
-    }
-};
-
 #endif // _ENGINE_H

src/event.h

@@ -52,4 +52,11 @@ class LockEvent : public Event {
     long long _timeout;
 };
 
+class LiveObject : public Event {
+  public:
+    u32 _class_id;
+    u64 _alloc_size;
+    u64 _alloc_time;
+};
+
 #endif // _EVENT_H

src/fdtransfer/fdtransfer.h

@@ -0,0 +1,98 @@
+/*
+ * Copyright 2021 Andrei Pangin
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef _FDTRANSFER_H
+#define _FDTRANSFER_H
+
+#ifdef __linux__
+
+#include <linux/perf_event.h>
+#include <stdio.h>
+#include <sys/socket.h>
+#include <sys/un.h>
+
+#define ARRAY_SIZE(arr)  (sizeof(arr) / sizeof(arr[0]))
+
+#define RESTARTABLE(call)  ({ ssize_t ret; while ((ret = call) < 0 && errno == EINTR); ret; })
+
+
+// base header for all requests
+enum request_type {
+    PERF_FD,
+    KALLSYMS_FD,
+    BPFMAP_FD,
+};
+
+struct fd_request {
+    // of type "enum request_type"
+    unsigned int type;
+};
+
+struct perf_fd_request {
+    struct fd_request header;
+    int tid;
+    struct perf_event_attr attr;
+};
+
+struct bpfmap_fd_request {
+    struct fd_request header;
+    int version;
+};
+
+struct fd_response {
+    // of type "enum request_type"
+    unsigned int type;
+    // 0 on success, otherwise errno
+    int error;
+};
+
+struct perf_fd_response {
+    struct fd_response header;
+    int tid;
+};
+
+struct bpfmap_params {
+    unsigned long interval;
+    unsigned int num_entries;
+    unsigned int entry_size;
+    unsigned int salt;
+};
+
+struct bpfmap_fd_response {
+    struct fd_response header;
+    struct bpfmap_params params;
+};
+
+
+static inline bool socketPath(const char *path, struct sockaddr_un *sun, socklen_t *addrlen) {
+    const int path_len = strlen(path);
+    if (path_len > sizeof(sun->sun_path)) {
+        return false;
+    }
+    memcpy(sun->sun_path, path, path_len);
+    if (sun->sun_path[0] == '@') {
+        sun->sun_path[0] = '\0';
+    }
+
+    sun->sun_family = AF_UNIX;
+    *addrlen = sizeof(*sun) - (sizeof(sun->sun_path) - path_len);
+
+    return true;
+}
+
+#endif // __linux__
+
+#endif // _FDTRANSFER_H

src/fdtransfer/fdtransferServer.cpp

@@ -0,0 +1,388 @@
+/*
+ * Copyright 2021 Andrei Pangin
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <signal.h>
+#include <time.h>
+#include <unistd.h>
+#include <sys/mman.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/sendfile.h>
+#include <sys/syscall.h>
+#include <sys/wait.h>
+
+#include "fdtransfer.h"
+#include "../jattach/psutil.h"
+
+
+class FdTransferServer {
+  private:
+    static int _server;
+    static int _peer;
+    static int copyFile(const char* src_name, const char* dst_name, mode_t mode);
+    static bool sendFd(int fd, struct fd_response *resp, size_t resp_size);
+
+  public:
+    static void closeServer() { close(_server); }
+    static void closePeer() { close(_peer); }
+    static bool bindServer(struct sockaddr_un *sun, socklen_t addrlen, int accept_timeout);
+    static bool acceptPeer(int *peer_pid);
+    static bool serveRequests(int peer_pid);
+};
+
+int FdTransferServer::_server;
+int FdTransferServer::_peer;
+
+bool FdTransferServer::bindServer(struct sockaddr_un *sun, socklen_t addrlen, int accept_timeout) {
+    _server = socket(AF_UNIX, SOCK_SEQPACKET, 0);
+    if (_server == -1) {
+        perror("FdTransfer socket()");
+        return false;
+    }
+
+    // Arbitrary timeout, to prevent it from listening forever.
+    if (accept_timeout > 0) {
+        const struct timeval timeout = {accept_timeout, 0};
+        if (setsockopt(_server, SOL_SOCKET, SO_RCVTIMEO, &timeout, sizeof(timeout)) < 0) {
+            perror("FdTransfer setsockopt(SO_RCVTIMEO)");
+            close(_server);
+            return false;
+        }
+    }
+
+    if (bind(_server, (const struct sockaddr*)sun, addrlen) < 0) {
+        perror("FdTransfer bind()");
+        close(_server);
+        return false;
+    }
+
+    if (listen(_server, 1) < 0) {
+        perror("FdTransfer listen()");
+        close(_server);
+        return false;
+    }
+
+    return true;
+}
+
+bool FdTransferServer::acceptPeer(int *peer_pid) {
+    _peer = accept(_server, NULL, NULL);
+    if (_peer == -1) {
+        perror("FdTransfer accept()");
+        return false;
+    }
+
+    struct ucred cred;
+    socklen_t len = sizeof(cred);
+    if (getsockopt(_peer, SOL_SOCKET, SO_PEERCRED, &cred, &len) == -1) {
+        perror("getsockopt(SO_PEERCRED)");
+        close(_peer);
+        return false;
+    }
+
+    if (*peer_pid != 0) {
+        if (cred.pid != *peer_pid) {
+            fprintf(stderr, "Unexpected connection from PID %d, expected from %d\n", cred.pid, *peer_pid);
+            close(_peer);
+            return false;
+        }
+    } else {
+        *peer_pid = cred.pid;
+    }
+
+    return true;
+}
+
+bool FdTransferServer::serveRequests(int peer_pid) {
+    // Close the server side, don't need it anymore.
+    FdTransferServer::closeServer();
+
+    void *perf_mmap_ringbuf[1024] = {};
+    size_t ringbuf_index = 0;
+    const size_t perf_mmap_size = 2 * sysconf(_SC_PAGESIZE);
+
+    while (1) {
+        unsigned char request_buf[1024];
+        struct fd_request *req = (struct fd_request *)request_buf;
+
+        ssize_t ret = RESTARTABLE(recv(_peer, req, sizeof(request_buf), 0));
+
+        if (ret == 0) {
+            // EOF means done
+            return true;
+        } else if (ret < 0) {
+            perror("recv()");
+            break;
+        }
+
+        switch (req->type) {
+        case PERF_FD: {
+            struct perf_fd_request *request = (struct perf_fd_request*)req;
+            int perf_fd = -1;
+            int error;
+
+            // In pid == 0 mode, allow all perf_event_open requests.
+            // Otherwise, verify the thread belongs to PID.
+            if (peer_pid == 0 || syscall(__NR_tgkill, peer_pid, request->tid, 0) == 0) {
+                perf_fd = syscall(__NR_perf_event_open, &request->attr, request->tid, -1, -1, 0);
+                error = perf_fd < 0 ? errno : 0;
+            } else {
+                fprintf(stderr, "Target has requested perf_event_open for TID %d which is not a thread of process %d\n", request->tid, peer_pid);
+                error = ESRCH;
+            }
+
+            // Map the perf buffer here (mapping perf fds may require privileges, and fdtransfer has them while the target application does not
+            // necessarily; if pages are already mapped, the same physical pages will be used when the profiler agent maps them again, requiring
+            // no privileges this time)
+            if (error == 0) {
+                // Settings match the mmap() done in PerfEvents::createForThread().
+                void *map_result = mmap(NULL, perf_mmap_size, PROT_READ | PROT_WRITE, MAP_SHARED, perf_fd, 0);
+                // Ignore errors - if this fails, let it fail again in the profiler again & produce a proper error for the user.
+
+                // Free next entry in the ring buffer, if it was previously allocated.
+                if (perf_mmap_ringbuf[ringbuf_index] != NULL && perf_mmap_ringbuf[ringbuf_index] != MAP_FAILED) {
+                    (void)munmap(perf_mmap_ringbuf[ringbuf_index], perf_mmap_size);
+                }
+                // Store it in the ring buffer so we can free it later.
+                perf_mmap_ringbuf[ringbuf_index] = map_result;
+
+                ringbuf_index++;
+                ringbuf_index = ringbuf_index % ARRAY_SIZE(perf_mmap_ringbuf);
+            }
+
+            struct perf_fd_response resp;
+            resp.header.type = request->header.type;
+            resp.header.error = error;
+            resp.tid = request->tid;
+            sendFd(perf_fd, &resp.header, sizeof(resp));
+            close(perf_fd);
+            break;
+        }
+
+        case KALLSYMS_FD: {
+            // can't directly pass the fd of /proc/kallsyms, because before Linux 4.15 the permission check
+            // was conducted on each read.
+            // it's simpler to copy the file to a temporary location and pass the fd of it (compared to passing the
+            // entire contents over the peer socket)
+            char tmp_path[256];
+            snprintf(tmp_path, sizeof(tmp_path), "/tmp/async-profiler-kallsyms.%d", getpid());
+
+            int kallsyms_fd = -1;
+            int error = copyFile("/proc/kallsyms", tmp_path, 0600);
+            if (error == 0) {
+                kallsyms_fd = open(tmp_path, O_RDONLY);
+                if (kallsyms_fd == -1) {
+                    error = errno;
+                } else {
+                    unlink(tmp_path);
+                }
+            }
+
+            struct fd_response resp;
+            resp.type = req->type;
+            resp.error = error;
+            sendFd(kallsyms_fd, &resp, sizeof(resp));
+            close(kallsyms_fd);
+            break;
+        }
+
+        default:
+            fprintf(stderr, "Unknown request type %u\n", req->type);
+            break;
+        }
+    }
+
+    return false;
+}
+
+int FdTransferServer::copyFile(const char* src_name, const char* dst_name, mode_t mode) {
+    int src = open(src_name, O_RDONLY);
+    if (src == -1) {
+        return errno;
+    }
+
+    int dst = creat(dst_name, mode);
+    if (dst == -1) {
+        int result = errno;
+        close(src);
+        return result;
+    }
+
+    // copy_file_range() doesn't exist in older kernels, sendfile() no longer works in newer ones
+    char buf[65536];
+    ssize_t r;
+    while ((r = read(src, buf, sizeof(buf))) > 0) {
+        ssize_t w = write(dst, buf, r);
+        (void)w;
+    }
+
+    close(dst);
+    close(src);
+    return 0;
+}
+
+bool FdTransferServer::sendFd(int fd, struct fd_response *resp, size_t resp_size) {
+    struct msghdr msg = {0};
+
+    struct iovec iov[1];
+    iov[0].iov_base = resp;
+    iov[0].iov_len = resp_size;
+    msg.msg_iov = iov;
+    msg.msg_iovlen = ARRAY_SIZE(iov);
+
+    union {
+       char buf[CMSG_SPACE(sizeof(fd))];
+       struct cmsghdr align;
+    } u;
+
+    if (fd != -1) {
+        msg.msg_control = u.buf;
+        msg.msg_controllen = sizeof(u.buf);
+
+        struct cmsghdr *cmsg = CMSG_FIRSTHDR(&msg);
+        cmsg->cmsg_level = SOL_SOCKET;
+        cmsg->cmsg_type = SCM_RIGHTS;
+        cmsg->cmsg_len = CMSG_LEN(sizeof(fd));
+        memcpy(CMSG_DATA(cmsg), &fd, sizeof(fd));
+    }
+
+    ssize_t ret = RESTARTABLE(sendmsg(_peer, &msg, 0));
+    if (ret < 0) {
+        perror("sendmsg()");
+        return false;
+    }
+
+    return true;
+}
+
+static int single_pid_server(int pid, const char *path) {
+    // get its nspid prior to moving to its PID namespace.
+    int nspid;
+    uid_t _target_uid;
+    gid_t _target_gid;
+    if (get_process_info(pid, &_target_uid, &_target_gid, &nspid)) {
+        fprintf(stderr, "Process %d not found\n", pid);
+        return 1;
+    }
+
+    struct sockaddr_un sun;
+    socklen_t addrlen;
+    if (!socketPath(path, &sun, &addrlen)) {
+        fprintf(stderr, "Path too long\n");
+        return 1;
+    }
+
+    // Create the server before forking, so w're ready to accept connections once our parent
+    // exits.
+
+    // Abstract namespace UDS requires us to move network namespace.
+    if (sun.sun_path[0] == '\0') {
+        if (enter_ns(pid, "net") == -1) {
+            fprintf(stderr, "Failed to enter the net NS of target process %d\n", pid);
+            return 1;
+        }
+    }
+
+    if (!FdTransferServer::bindServer(&sun, addrlen, 10)) {
+        return 1;
+    }
+
+    if (!enter_ns(pid, "pid") == -1) {
+        fprintf(stderr, "Failed to enter the PID NS of target process %d\n", pid);
+        return 1;
+    }
+
+    // CLONE_NEWPID affects children only - so we fork here.
+    if (0 == fork()) {
+        return FdTransferServer::acceptPeer(&nspid) && FdTransferServer::serveRequests(nspid) ? 0 : 1;
+    } else {
+        // Exit now, let our caller continue.
+        return 0;
+    }
+}
+
+static int path_server(const char *path) {
+    struct sockaddr_un sun;
+    socklen_t addrlen;
+
+    struct sigaction sigchld_action;
+    sigchld_action.sa_handler = SIG_DFL;
+    sigchld_action.sa_flags = SA_NOCLDWAIT;
+    sigaction(SIGCHLD, &sigchld_action, NULL);
+
+    if (!socketPath(path, &sun, &addrlen)) {
+        fprintf(stderr, "Path '%s' is too long\n", path);
+        return 1;
+    }
+
+    if (!FdTransferServer::bindServer(&sun, addrlen, 0)) {
+        return 1;
+    }
+
+    printf("Server ready at '%s'\n", path);
+
+    while (1) {
+        int peer_pid = 0;
+        if (!FdTransferServer::acceptPeer(&peer_pid)) {
+            return 1;
+        }
+
+        // Enter its PID namespace.
+        if (enter_ns(peer_pid, "pid") == -1) {
+            fprintf(stderr, "Failed to enter the PID NS of target process %d\n", peer_pid);
+            return 1;
+        }
+
+        printf("Serving PID %d\n", peer_pid);
+
+        // We fork(), to actually move a PID namespace.
+        if (0 == fork()) {
+            return FdTransferServer::serveRequests(0) ? 0 : 1;
+        } else {
+            FdTransferServer::closePeer();
+        }
+
+        // Move back to our original PID namespace (reverts pid_for_children)
+        if (enter_ns(getpid(), "pid") == -1) {
+            fprintf(stderr, "Failed to exit the PID NS of target process %d\n", peer_pid);
+            return 1;
+        }
+    }
+}
+
+int main(int argc, const char** argv) {
+    int pid = 0;
+    if (argc == 3) {
+        pid = atoi(argv[2]);
+    } else if (argc != 2) {
+        fprintf(stderr, "Usage: %s <path> [<pid>]\n", argv[0]);
+        return 1;
+    }
+
+    // 2 modes:
+    // pid is not given - bind on a path and accept requests forever, from any PID, until being killed.
+    // pid is given     - bind on an path for that PID, accept requests only from that PID until the single connection is closed.
+    if (pid != 0) {
+        return single_pid_server(pid, argv[1]);
+    } else {
+        return path_server(argv[1]);
+    }
+}

src/fdtransferClient.h

@@ -0,0 +1,56 @@
+/*
+ * Copyright 2021 Andrei Pangin
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef _FDTRANSFER_CLIENT_H
+#define _FDTRANSFER_CLIENT_H
+
+#ifdef __linux__
+
+#include "fdtransfer/fdtransfer.h"
+
+class FdTransferClient {
+  private:
+    static int _peer;
+
+    static int recvFd(unsigned int request_id, struct fd_response *resp, size_t resp_size);
+
+  public:
+    static bool connectToServer(const char *path);
+    static bool hasPeer() { return _peer != -1; }
+    static void closePeer() {
+        if (_peer != -1) {
+            close(_peer);
+            _peer = -1;
+        }
+    }
+
+    static int requestPerfFd(int *tid, struct perf_event_attr *attr);
+    static int requestKallsymsFd();
+    static int requestBpfMapFd(struct bpfmap_params* params);
+};
+
+#else
+
+class FdTransferClient {
+  public:
+    static bool connectToServer(const char *path) { return false; }
+    static bool hasPeer() { return false; }
+    static void closePeer() { }
+};
+
+#endif // __linux__
+
+#endif // _FDTRANSFER_CLIENT_H

src/fdtransferClient_linux.cpp

@@ -0,0 +1,169 @@
+/*
+ * Copyright 2021 Andrei Pangin
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifdef __linux__
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <unistd.h>
+
+#include "fdtransferClient.h"
+#include "log.h"
+
+
+int FdTransferClient::_peer = -1;
+
+bool FdTransferClient::connectToServer(const char *path) {
+    closePeer();
+
+    _peer = socket(AF_UNIX, SOCK_SEQPACKET, 0);
+    if (_peer == -1) {
+        Log::warn("FdTransferClient socket(): %s", strerror(errno));
+        return false;
+    }
+
+    struct sockaddr_un sun;
+    socklen_t addrlen;
+    if (!socketPath(path, &sun, &addrlen)) {
+        return false;
+    }
+
+    // Do not block for more than 10 seconds when waiting for a response
+    struct timeval tv = {10, 0};
+    setsockopt(_peer, SOL_SOCKET, SO_RCVTIMEO, &tv, sizeof(tv));
+
+    if (connect(_peer, (const struct sockaddr *)&sun, addrlen) == -1) {
+        Log::warn("FdTransferClient connect(): %s", strerror(errno));
+        return false;
+    }
+
+    return true;
+}
+
+int FdTransferClient::requestPerfFd(int *tid, struct perf_event_attr *attr) {
+    struct perf_fd_request request;
+    request.header.type = PERF_FD;
+    request.tid = *tid;
+    memcpy(&request.attr, attr, sizeof(request.attr));
+
+    if (RESTARTABLE(send(_peer, &request, sizeof(request), 0)) != sizeof(request)) {
+        Log::warn("FdTransferClient send(): %s", strerror(errno));
+        return -1;
+    }
+
+    struct perf_fd_response resp;
+    int fd = recvFd(request.header.type, &resp.header, sizeof(resp));
+    if (fd == -1) {
+        // Update errno for our caller.
+        errno = resp.header.error;
+    } else {
+        // Update the TID of createForThread, in case the multiple threads' requests got mixed up and we're
+        // now handling the response destined to another. It's alright - the other thread(s) will finish the
+        // handling of our TID perf fd.
+        *tid = resp.tid;
+    }
+    return fd;
+}
+
+int FdTransferClient::requestKallsymsFd() {
+    struct fd_request request;
+    request.type = KALLSYMS_FD;
+
+    if (RESTARTABLE(send(_peer, &request, sizeof(request), 0)) != sizeof(request)) {
+        Log::warn("FdTransferClient send(): %s", strerror(errno));
+        return -1;
+    }
+
+    struct fd_response resp;
+    int fd = recvFd(request.type, &resp, sizeof(resp));
+    if (fd == -1) {
+        errno = resp.error;
+    }
+
+    return fd;
+}
+
+int FdTransferClient::requestBpfMapFd(struct bpfmap_params* params) {
+    struct bpfmap_fd_request request;
+    request.header.type = BPFMAP_FD;
+    request.version = 1;
+
+    if (RESTARTABLE(send(_peer, &request, sizeof(request), 0)) != sizeof(request)) {
+        Log::warn("FdTransferClient send(): %s", strerror(errno));
+        return -1;
+    }
+
+    struct bpfmap_fd_response resp;
+    int fd = recvFd(request.header.type, &resp.header, sizeof(resp));
+    if (fd == -1) {
+        errno = resp.header.error;
+    } else {
+        *params = resp.params;
+    }
+    return fd;
+}
+
+int FdTransferClient::recvFd(unsigned int type, struct fd_response *resp, size_t resp_size) {
+    struct msghdr msg = {0};
+
+    struct iovec iov[1];
+    iov[0].iov_base = resp;
+    iov[0].iov_len = resp_size;
+    msg.msg_iov = iov;
+    msg.msg_iovlen = ARRAY_SIZE(iov);
+
+    int newfd;
+    union {
+        char buf[CMSG_SPACE(sizeof(newfd))];
+        struct cmsghdr align;
+    } u;
+    msg.msg_control = u.buf;
+    msg.msg_controllen = sizeof(u.buf);
+
+    ssize_t ret = RESTARTABLE(recvmsg(_peer, &msg, 0));
+    if (ret < 0) {
+        Log::warn("FdTransferClient recvmsg(): %s", strerror(errno));
+        return -1;
+    }
+
+    if (resp->type != type) {
+        Log::warn("FdTransferClient recvmsg(): bad response type");
+        return -1;
+    }
+
+    if (resp->error == 0) {
+        struct cmsghdr *cmptr = CMSG_FIRSTHDR(&msg);
+        if (cmptr != NULL && cmptr->cmsg_len == CMSG_LEN(sizeof(newfd))
+            && cmptr->cmsg_level == SOL_SOCKET && cmptr->cmsg_type == SCM_RIGHTS) {
+
+            newfd = *((int*)CMSG_DATA(cmptr));
+        } else {
+            Log::warn("FdTransferClient recvmsg(): unexpected response with no SCM_RIGHTS: %s", strerror(errno));
+            newfd = -1;
+        }
+    } else {
+        newfd = -1;
+    }
+
+    return newfd;
+}
+
+#endif // __linux__

src/flameGraph.cpp

@@ -17,393 +17,17 @@
 #include <algorithm>
 #include <vector>
 #include <stdio.h>
+#include <string.h>
 #include "flameGraph.h"
+#include "incbin.h"
+#include "vmEntry.h"
 
 
-static const char FLAMEGRAPH_HEADER[] =
-    "<!DOCTYPE html>\n"
-    "<html lang='en'>\n"
-    "<head>\n"
-    "<meta charset='utf-8'>\n"
-    "<style>\n"
-    "\tbody {margin: 0; padding: 10px; background-color: #ffffff}\n"
-    "\th1 {margin: 5px 0 0 0; font-size: 18px; font-weight: normal; text-align: center}\n"
-    "\theader {margin: -24px 0 5px 0; line-height: 24px}\n"
-    "\tbutton {font: 12px sans-serif; cursor: pointer}\n"
-    "\tp {margin: 5px 0 5px 0}\n"
-    "\ta {color: #0366d6}\n"
-    "\t#hl {position: absolute; display: none; overflow: hidden; white-space: nowrap; pointer-events: none; background-color: #ffffe0; outline: 1px solid #ffc000; height: 15px}\n"
-    "\t#hl span {padding: 0 3px 0 3px}\n"
-    "\t#status {overflow: hidden; white-space: nowrap}\n"
-    "\t#match {overflow: hidden; white-space: nowrap; display: none; float: right; text-align: right}\n"
-    "\t#reset {cursor: pointer}\n"
-    "</style>\n"
-    "</head>\n"
-    "<body style='font: 12px Verdana, sans-serif'>\n"
-    "<h1>%s</h1>\n"
-    "<header style='text-align: left'><button id='reverse' title='Reverse'>&#x1f53b;</button>&nbsp;&nbsp;<button id='search' title='Search'>&#x1f50d;</button></header>\n"
-    "<header style='text-align: right'>Produced by <a href='https://github.com/jvm-profiling-tools/async-profiler'>async-profiler</a></header>\n"
-    "<canvas id='canvas' style='width: 100%%; height: %dpx'></canvas>\n"
-    "<div id='hl'><span></span></div>\n"
-    "<p id='match'>Matched: <span id='matchval'></span> <span id='reset' title='Clear'>&#x274c;</span></p>\n"
-    "<p id='status'>&nbsp;</p>\n"
-    "<script>\n"
-    "\t// Copyright 2020 Andrei Pangin\n"
-    "\t// Licensed under the Apache License, Version 2.0.\n"
-    "\t'use strict';\n"
-    "\tvar root, rootLevel, px, pattern;\n"
-    "\tvar reverse = %s;\n"
-    "\tconst levels = Array(%d);\n"
-    "\tfor (let h = 0; h < levels.length; h++) {\n"
-    "\t\tlevels[h] = [];\n"
-    "\t}\n"
-    "\n"
-    "\tconst canvas = document.getElementById('canvas');\n"
-    "\tconst c = canvas.getContext('2d');\n"
-    "\tconst hl = document.getElementById('hl');\n"
-    "\tconst status = document.getElementById('status');\n"
-    "\n"
-    "\tconst canvasWidth = canvas.offsetWidth;\n"
-    "\tconst canvasHeight = canvas.offsetHeight;\n"
-    "\tcanvas.style.width = canvasWidth + 'px';\n"
-    "\tcanvas.width = canvasWidth * (devicePixelRatio || 1);\n"
-    "\tcanvas.height = canvasHeight * (devicePixelRatio || 1);\n"
-    "\tif (devicePixelRatio) c.scale(devicePixelRatio, devicePixelRatio);\n"
-    "\tc.font = document.body.style.font;\n"
-    "\n"
-    "\tconst palette = [\n"
-    "\t\t[0x50e150, 30, 30, 30],\n"
-    "\t\t[0x50bebe, 30, 30, 30],\n"
-    "\t\t[0xe17d00, 30, 30,  0],\n"
-    "\t\t[0xc8c83c, 30, 30, 10],\n"
-    "\t\t[0xe15a5a, 30, 40, 40],\n"
-    "\t];\n"
-    "\n"
-    "\tfunction getColor(p) {\n"
-    "\t\tconst v = Math.random();\n"
-    "\t\treturn '#' + (p[0] + ((p[1] * v) << 16 | (p[2] * v) << 8 | (p[3] * v))).toString(16);\n"
-    "\t}\n"
-    "\n"
-    "\tfunction f(level, left, width, type, title) {\n"
-    "\t\tlevels[level].push({left: left, width: width, color: getColor(palette[type]), title: title});\n"
-    "\t}\n"
-    "\n"
-    "\tfunction samples(n) {\n"
-    "\t\treturn n === 1 ? '1 sample' : n.toString().replace(/\\B(?=(\\d{3})+(?!\\d))/g, ',') + ' samples';\n"
-    "\t}\n"
-    "\n"
-    "\tfunction pct(a, b) {\n"
-    "\t\treturn a >= b ? '100' : (100 * a / b).toFixed(2);\n"
-    "\t}\n"
-    "\n"
-    "\tfunction findFrame(frames, x) {\n"
-    "\t\tlet left = 0;\n"
-    "\t\tlet right = frames.length - 1;\n"
-    "\n"
-    "\t\twhile (left <= right) {\n"
-    "\t\t\tconst mid = (left + right) >>> 1;\n"
-    "\t\t\tconst f = frames[mid];\n"
-    "\n"
-    "\t\t\tif (f.left > x) {\n"
-    "\t\t\t\tright = mid - 1;\n"
-    "\t\t\t} else if (f.left + f.width <= x) {\n"
-    "\t\t\t\tleft = mid + 1;\n"
-    "\t\t\t} else {\n"
-    "\t\t\t\treturn f;\n"
-    "\t\t\t}\n"
-    "\t\t}\n"
-    "\n"
-    "\t\tif (frames[left] && (frames[left].left - x) * px < 0.5) return frames[left];\n"
-    "\t\tif (frames[right] && (x - (frames[right].left + frames[right].width)) * px < 0.5) return frames[right];\n"
-    "\n"
-    "\t\treturn null;\n"
-    "\t}\n"
-    "\n"
-    "\tfunction search(r) {\n"
-    "\t\tif (r && (r = prompt('Enter regexp to search:', '')) === null) {\n"
-    "\t\t\treturn;\n"
-    "\t\t}\n"
-    "\n"
-    "\t\tpattern = r ? RegExp(r) : undefined;\n"
-    "\t\tconst matched = render(root, rootLevel);\n"
-    "\t\tdocument.getElementById('matchval').textContent = pct(matched, root.width) + '%%';\n"
-    "\t\tdocument.getElementById('match').style.display = r ? 'inherit' : 'none';\n"
-    "\t}\n"
-    "\n"
-    "\tfunction render(newRoot, newLevel) {\n"
-    "\t\tif (root) {\n"
-    "\t\t\tc.fillStyle = '#ffffff';\n"
-    "\t\t\tc.fillRect(0, 0, canvasWidth, canvasHeight);\n"
-    "\t\t}\n"
-    "\n"
-    "\t\troot = newRoot || levels[0][0];\n"
-    "\t\trootLevel = newLevel || 0;\n"
-    "\t\tpx = canvasWidth / root.width;\n"
-    "\n"
-    "\t\tconst x0 = root.left;\n"
-    "\t\tconst x1 = x0 + root.width;\n"
-    "\t\tconst marked = [];\n"
-    "\n"
-    "\t\tfunction mark(f) {\n"
-    "\t\t\treturn marked[f.left] >= f.width || (marked[f.left] = f.width);\n"
-    "\t\t}\n"
-    "\n"
-    "\t\tfunction totalMarked() {\n"
-    "\t\t\tlet total = 0;\n"
-    "\t\t\tlet left = 0;\n"
-    "\t\t\tfor (let x in marked) {\n"
-    "\t\t\t\tif (+x >= left) {\n"
-    "\t\t\t\t\ttotal += marked[x];\n"
-    "\t\t\t\t\tleft = +x + marked[x];\n"
-    "\t\t\t\t}\n"
-    "\t\t\t}\n"
-    "\t\t\treturn total;\n"
-    "\t\t}\n"
-    "\n"
-    "\t\tfunction drawFrame(f, y, alpha) {\n"
-    "\t\t\tif (f.left < x1 && f.left + f.width > x0) {\n"
-    "\t\t\t\tc.fillStyle = pattern && f.title.match(pattern) && mark(f) ? '#ee00ee' : f.color;\n"
-    "\t\t\t\tc.fillRect((f.left - x0) * px, y, f.width * px, 15);\n"
-    "\n"
-    "\t\t\t\tif (f.width * px >= 21) {\n"
-    "\t\t\t\t\tconst chars = Math.floor(f.width * px / 7);\n"
-    "\t\t\t\t\tconst title = f.title.length <= chars ? f.title : f.title.substring(0, chars - 2) + '..';\n"
-    "\t\t\t\t\tc.fillStyle = '#000000';\n"
-    "\t\t\t\t\tc.fillText(title, Math.max(f.left - x0, 0) * px + 3, y + 12, f.width * px - 6);\n"
-    "\t\t\t\t}\n"
-    "\n"
-    "\t\t\t\tif (alpha) {\n"
-    "\t\t\t\t\tc.fillStyle = 'rgba(255, 255, 255, 0.5)';\n"
-    "\t\t\t\t\tc.fillRect((f.left - x0) * px, y, f.width * px, 15);\n"
-    "\t\t\t\t}\n"
-    "\t\t\t}\n"
-    "\t\t}\n"
-    "\n"
-    "\t\tfor (let h = 0; h < levels.length; h++) {\n"
-    "\t\t\tconst y = reverse ? h * 16 : canvasHeight - (h + 1) * 16;\n"
-    "\t\t\tconst frames = levels[h];\n"
-    "\t\t\tfor (let i = 0; i < frames.length; i++) {\n"
-    "\t\t\t\tdrawFrame(frames[i], y, h < rootLevel);\n"
-    "\t\t\t}\n"
-    "\t\t}\n"
-    "\n"
-    "\t\treturn totalMarked();\n"
-    "\t}\n"
-    "\n"
-    "\tcanvas.onmousemove = function() {\n"
-    "\t\tconst h = Math.floor((reverse ? event.offsetY : (canvasHeight - event.offsetY)) / 16);\n"
-    "\t\tif (h >= 0 && h < levels.length) {\n"
-    "\t\t\tconst f = findFrame(levels[h], event.offsetX / px + root.left);\n"
-    "\t\t\tif (f) {\n"
-    "\t\t\t\thl.style.left = (Math.max(f.left - root.left, 0) * px + canvas.offsetLeft) + 'px';\n"
-    "\t\t\t\thl.style.width = (Math.min(f.width, root.width) * px) + 'px';\n"
-    "\t\t\t\thl.style.top = ((reverse ? h * 16 : canvasHeight - (h + 1) * 16) + canvas.offsetTop) + 'px';\n"
-    "\t\t\t\thl.firstChild.textContent = f.title;\n"
-    "\t\t\t\thl.style.display = 'block';\n"
-    "\t\t\t\tcanvas.title = f.title + '\\n(' + samples(f.width) + ', ' + pct(f.width, levels[0][0].width) + '%%)';\n"
-    "\t\t\t\tcanvas.style.cursor = 'pointer';\n"
-    "\t\t\t\tcanvas.onclick = function() {\n"
-    "\t\t\t\t\tif (f != root) {\n"
-    "\t\t\t\t\t\trender(f, h);\n"
-    "\t\t\t\t\t\tcanvas.onmousemove();\n"
-    "\t\t\t\t\t}\n"
-    "\t\t\t\t};\n"
-    "\t\t\t\tstatus.textContent = 'Function: ' + canvas.title;\n"
-    "\t\t\t\treturn;\n"
-    "\t\t\t}\n"
-    "\t\t}\n"
-    "\t\tcanvas.onmouseout();\n"
-    "\t}\n"
-    "\n"
-    "\tcanvas.onmouseout = function() {\n"
-    "\t\thl.style.display = 'none';\n"
-    "\t\tstatus.textContent = '\\xa0';\n"
-    "\t\tcanvas.title = '';\n"
-    "\t\tcanvas.style.cursor = '';\n"
-    "\t\tcanvas.onclick = '';\n"
-    "\t}\n"
-    "\n"
-    "\tdocument.getElementById('reverse').onclick = function() {\n"
-    "\t\treverse = !reverse;\n"
-    "\t\trender();\n"
-    "\t}\n"
-    "\n"
-    "\tdocument.getElementById('search').onclick = function() {\n"
-    "\t\tsearch(true);\n"
-    "\t}\n"
-    "\n"
-    "\tdocument.getElementById('reset').onclick = function() {\n"
-    "\t\tsearch(false);\n"
-    "\t}\n"
-    "\n"
-    "\twindow.onkeydown = function() {\n"
-    "\t\tif (event.ctrlKey && event.keyCode === 70) {\n"
-    "\t\t\tevent.preventDefault();\n"
-    "\t\t\tsearch(true);\n"
-    "\t\t} else if (event.keyCode === 27) {\n"
-    "\t\t\tsearch(false);\n"
-    "\t\t}\n"
-    "\t}\n";
+// Browsers refuse to draw on canvas larger than 32767 px
+const int MAX_CANVAS_HEIGHT = 32767;
 
-static const char FLAMEGRAPH_FOOTER[] =
-    "render();\n"
-    "</script></body></html>\n";
-
-
-static const char TREE_HEADER[] =
-    "<!DOCTYPE html>\n"
-    "<html lang=\"en\">\n"
-    "<head>\n"
-    "<title>Tree view</title>\n"
-    "<meta charset=\"utf-8\"/>\n"
-    "<style>\n"
-    "body {\n"
-    "    font-family: Arial;\n"
-    "}\n"
-    "ul.tree li {\n"
-    "    list-style-type: none;\n"
-    "    position: relative;\n"
-    "}\n"
-    "ul.tree ul {\n"
-    "    margin-left: 20px; padding-left: 0;\n"
-    "}\n"
-    "ul.tree li ul {\n"
-    "    display: none;\n"
-    "}\n"
-    "ul.tree li.open > ul {\n"
-    "    display: block;\n"
-    "}\n"
-    "ul.tree li div:before {\n"
-    "    height: 1em;\n"
-    "    padding:0 .1em;\n"
-    "    font-size: .8em;\n"
-    "    display: block;\n"
-    "    position: absolute;\n"
-    "    left: -1.3em;\n"
-    "    top: .2em;\n"
-    "}\n"
-    "ul.tree li > div:not(:nth-last-child(2)):before {\n"
-    "    content: '+';\n"
-    "}\n"
-    "ul.tree li.open > div:not(:nth-last-child(2)):before {\n"
-    "    content: '-';\n"
-    "}\n"
-    ".sc {\n"
-    "    text-decoration: underline;\n"
-    "    text-decoration-color: black;\n"
-    "    font-weight: bold;\n"
-    "    background-color: #D9D9D9;\n"
-    "}\n"
-    ".t0 {\n"
-    "    color: #32c832;\n"
-    "}\n"
-    ".t1 {\n"
-    "    color: #32a5a5;\n"
-    "}\n"
-    ".t2 {\n"
-    "    color: #be5a00;\n"
-    "}\n"
-    ".t3 {\n"
-    "    color: #afaf32;\n"
-    "}\n"
-    ".t4 {\n"
-    "    color: #c83232;\n"
-    "}\n"
-    "ul.tree li > div {\n"
-    "    display: inline;\n"
-    "    cursor: pointer;\n"
-    "    color: black;\n"
-    "    text-decoration: none;\n"
-    "}\n"
-    "</style>\n"
-    "<script>\n"
-    "function treeView(opt) {\n"
-    "    var tree = document.querySelectorAll('ul.tree div:not(:last-child)');\n"
-    "    for(var i = 0; i < tree.length; i++){\n"
-    "        var parent = tree[i].parentElement;\n"
-    "        var classList = parent.classList;\n"
-    "        if(opt == 0) {\n"
-    "            classList.add('open');\n"
-    "        } else {\n"
-    "            classList.remove('open');\n"
-    "        }\n"
-    "    }\n"
-    "}\n"
-    "function openParent(p,t) {\n"
-    "    if(p.parentElement.classList.contains(\"tree\")) {\n"
-    "        return;\n"
-    "    }\n"
-    "    p.parentElement.classList.add('open');\n"
-    "    openParent(p.parentElement,t);\n"
-    "}\n"
-    "function search() {\n"
-    "    var tree = document.querySelectorAll('ul.tree span');\n"
-    "    var check = document.getElementById('check');\n"
-    "    for(var i = 0; i < tree.length; i++){\n"
-    "        tree[i].classList.remove('sc');\n"
-    "        if(tree[i].innerHTML.includes(document.getElementById(\"search\").value)) {\n"
-    "            tree[i].classList.add('sc');\n"
-    "            openParent(tree[i].parentElement,tree);\n"
-    "        }\n"
-    "    }\n"
-    "}\n"
-    "function openUL(n) {\n"
-    "    var children = n.children;\n"
-    "    if(children.length == 1) {\n"
-    "        openNode(children[0]);\n"
-    "    }\n"
-    "}\n"
-    "function openNode(n) {\n"
-    "    var children = n.children;\n"
-    "    for(var i = 0; i < children.length; i++){\n"
-    "        if(children[i].nodeName == 'UL') {\n"
-    "            n.classList.add('open');\n"
-    "            openUL(children[i]);\n"
-    "        }\n"
-    "    }\n"
-    "}\n"
-    "function addClickActions() {\n"
-    "var tree = document.querySelectorAll('ul.tree div:not(:last-child)');\n"
-    "for(var i = 0; i < tree.length; i++){\n"
-    "    tree[i].addEventListener('click', function(e) {\n"
-    "        var parent = e.target.parentElement;\n"
-    "        var classList = parent.classList;\n"
-    "        if(classList.contains(\"open\")) {\n"
-    "            classList.remove('open');\n"
-    "            var opensubs = parent.querySelectorAll(':scope .open');\n"
-    "            for(var i = 0; i < opensubs.length; i++){\n"
-    "                opensubs[i].classList.remove('open');\n"
-    "            }\n"
-    "        } else {\n"
-    "            if(e.altKey) {\n"
-    "                classList.add('open');\n"
-    "                var opensubs = parent.querySelectorAll('li');\n"
-    "                for(var i = 0; i < opensubs.length; i++){\n"
-    "                    opensubs[i].classList.add('open');\n"
-    "                }\n"
-    "            } else {\n"
-    "                openNode(parent);\n"
-    "            }\n"
-    "        }\n"
-    "    });\n"
-    "}\n"
-    "}\n"
-    "</script>\n"
-    "</head>\n"
-    "<body>\n"
-    "<div style=\"padding-left: 25px;\">%s view, total %s: %s </div>\n"
-    "<div style=\"padding-left: 25px;\"><button type='button' onclick='treeView(0)'>++</button><button type='button' onclick='treeView(1)'>--</button>\n"
-    "<input type='text' id='search' value='' size='35' onkeypress=\"if(event.keyCode == 13) document.getElementById('searchBtn').click()\">\n"
-    "<button type='button' id='searchBtn' onclick='search()'>search</button></div>\n"
-    "<ul class=\"tree\">\n";
-
-static const char TREE_FOOTER[] = 
-    "<script>\n"
-    "addClickActions();\n"
-    "</script>\n"
-    "</ul>\n"
-    "</body>\n"
-    "</html>\n";
+INCBIN(FLAMEGRAPH_TEMPLATE, "flame.html")
+INCBIN(TREE_TEMPLATE, "tree.html")
 
 
 class StringUtils {
@@ -413,9 +37,9 @@ class StringUtils {
         return len >= suffixlen && s.compare(len - suffixlen, suffixlen, suffix) == 0; 
     }
 
-    static void replace(std::string& s, char c, const char* replacement) {
-        for (size_t i = 0; (i = s.find(c, i)) != std::string::npos; i++) {
-            s.replace(i, 1, replacement);
+    static void replace(std::string& s, char c, const char* replacement, size_t rlen) {
+        for (size_t i = 0; (i = s.find(c, i)) != std::string::npos; i += rlen) {
+            s.replace(i, 1, replacement, rlen);
         }
     }
 };
@@ -467,33 +91,59 @@ void FlameGraph::dump(std::ostream& out, bool tree) {
     int depth = _root.depth(_mintotal);
 
     if (tree) {
-        char buf[sizeof(TREE_HEADER) + 256];
-        snprintf(buf, sizeof(buf) - 1, TREE_HEADER,
-                 _reverse ? "Backtrace" : "Call tree",
-                 _counter ==  COUNTER_SAMPLES ? "samples" : "counter",
-                 Format().thousands(_root._total));
-        out << buf;
+        const char* tail = TREE_TEMPLATE;
+
+        tail = printTill(out, tail, "/*title:*/");
+        out << (_reverse ? "Backtrace" : "Call tree");
+
+        tail = printTill(out, tail, "/*type:*/");
+        out << (_counter == COUNTER_SAMPLES ? "samples" : "counter");
+
+        tail = printTill(out, tail, "/*count:*/");
+        out << Format().thousands(_root._total);
+
+        tail = printTill(out, tail, "/*tree:*/");
 
         printTreeFrame(out, _root, 0);
 
-        out << TREE_FOOTER;
+        out << tail;
     } else {
-        char buf[sizeof(FLAMEGRAPH_HEADER) + 256];
-        snprintf(buf, sizeof(buf) - 1, FLAMEGRAPH_HEADER, _title, depth * 16, _reverse ? "true" : "false", depth);
-        out << buf;
+        const char* tail = FLAMEGRAPH_TEMPLATE;
+
+        tail = printTill(out, tail, "/*height:*/300");
+        out << std::min(depth * 16, MAX_CANVAS_HEIGHT);
+
+        tail = printTill(out, tail, "/*title:*/");
+        out << _title;
+
+        tail = printTill(out, tail, "/*reverse:*/false");
+        out << (_reverse ? "true" : "false");
+
+        tail = printTill(out, tail, "/*depth:*/0");
+        out << depth;
+
+        tail = printTill(out, tail, "/*frames:*/");
 
         printFrame(out, "all", _root, 0, 0);
 
-        out << FLAMEGRAPH_FOOTER;
+        tail = printTill(out, tail, "/*highlight:*/");
+
+        out << tail;
     }
 }
 
 void FlameGraph::printFrame(std::ostream& out, const std::string& name, const Trie& f, int level, u64 x) {
     std::string name_copy = name;
-    int type = frameType(name_copy);
-    StringUtils::replace(name_copy, '\'', "\\'");
+    int type = frameType(name_copy, f);
+    StringUtils::replace(name_copy, '\'', "\\'", 2);
 
-    snprintf(_buf, sizeof(_buf) - 1, "f(%d,%llu,%llu,%d,'%s')\n", level, x, f._total, type, name_copy.c_str());
+    if (f._inlined | f._c1_compiled | f._interpreted) {
+        snprintf(_buf, sizeof(_buf) - 1, "f(%d,%llu,%llu,%d,'%s',%llu,%llu,%llu)\n",
+                 level, x, f._total, type, name_copy.c_str(), f._inlined, f._c1_compiled, f._interpreted);
+    } else {
+        snprintf(_buf, sizeof(_buf) - 1, "f(%d,%llu,%llu,%d,'%s')\n",
+                 level, x, f._total, type, name_copy.c_str());
+    }
     out << _buf;
 
     x += f._self;
@@ -517,10 +167,10 @@ void FlameGraph::printTreeFrame(std::ostream& out, const Trie& f, int level) {
         std::string name = subnodes[i]._name;
         const Trie* trie = subnodes[i]._trie;
 
-        int type = frameType(name);
-        StringUtils::replace(name, '&', "&amp;");
-        StringUtils::replace(name, '<', "&lt;");
-        StringUtils::replace(name, '>', "&gt;");
+        int type = frameType(name, f);
+        StringUtils::replace(name, '&', "&amp;", 5);
+        StringUtils::replace(name, '<', "&lt;", 4);
+        StringUtils::replace(name, '>', "&gt;", 4);
 
         if (_reverse) {
             snprintf(_buf, sizeof(_buf) - 1,
@@ -550,27 +200,37 @@ void FlameGraph::printTreeFrame(std::ostream& out, const Trie& f, int level) {
     }
 }
 
-int FlameGraph::frameType(std::string& name) {
+const char* FlameGraph::printTill(std::ostream& out, const char* data, const char* till) {
+    const char* pos = strstr(data, till);
+    out.write(data, pos - data);
+    return pos + strlen(till);
+}
+
+// TODO: Reuse frame type embedded in ASGCT_CallFrame
+int FlameGraph::frameType(std::string& name, const Trie& f) {
+    if (f._inlined * 3 >= f._total) {
+        return FRAME_INLINED;
+    } else if (f._c1_compiled * 2 >= f._total) {
+        return FRAME_C1_COMPILED;
+    } else if (f._interpreted * 2 >= f._total) {
+        return FRAME_INTERPRETED;
+    }
+
     if (StringUtils::endsWith(name, "_[j]", 4)) {
-        // Java compiled frame
         name = name.substr(0, name.length() - 4);
-        return 0;
+        return FRAME_JIT_COMPILED;
     } else if (StringUtils::endsWith(name, "_[i]", 4)) {
-        // Java inlined frame
         name = name.substr(0, name.length() - 4);
-        return 1;
+        return FRAME_INLINED;
     } else if (StringUtils::endsWith(name, "_[k]", 4)) {
-        // Kernel function
         name = name.substr(0, name.length() - 4);
-        return 2;
+        return FRAME_KERNEL;
     } else if (name.find("::") != std::string::npos || name.compare(0, 2, "-[") == 0 || name.compare(0, 2, "+[") == 0) {
-        // C++ function or Objective C method
-        return 3;
-    } else if ((int)name.find('/') > 0 || ((int)name.find('.') > 0 && name[0] >= 'A' && name[0] <= 'Z')) {
-        // Java regular method
-        return 0;
+        return FRAME_CPP;
+    } else if (((int)name.find('/') > 0 && name[0] != '[')
+            || ((int)name.find('.') > 0 && name[0] >= 'A' && name[0] <= 'Z')) {
+        return FRAME_JIT_COMPILED;
     } else {
-        // Other native code
-        return 4;
+        return FRAME_NATIVE;
     }
 }

src/flameGraph.h

@@ -22,6 +22,7 @@
 #include <iostream>
 #include "arch.h"
 #include "arguments.h"
+#include "vmEntry.h"
 
 
 class Trie {
@@ -29,10 +30,11 @@ class Trie {
     std::map<std::string, Trie> _children;
     u64 _total;
     u64 _self;
+    u64 _inlined, _c1_compiled, _interpreted;
 
-    Trie() : _children(), _total(0), _self(0) {
+    Trie() : _children(), _total(0), _self(0), _inlined(0), _c1_compiled(0), _interpreted(0) {
     }
-    
+
     Trie* addChild(const std::string& key, u64 value) {
         _total += value;
         return &_children[key];
@@ -43,6 +45,15 @@ class Trie {
         _self += value;
     }
 
+    void addCompilationDetails(int bci, u64 counter) {
+        switch (FrameType::decode(bci)) {
+            case FRAME_INLINED:     _inlined += counter; break;
+            case FRAME_C1_COMPILED: _c1_compiled += counter; break;
+            case FRAME_INTERPRETED: _interpreted += counter; break;
+            default: break;
+        }
+    }
+
     int depth(u64 cutoff) const {
         if (_total < cutoff) {
             return 0;
@@ -71,7 +82,8 @@ class FlameGraph {
 
     void printFrame(std::ostream& out, const std::string& name, const Trie& f, int level, u64 x);
     void printTreeFrame(std::ostream& out, const Trie& f, int level);
-    int frameType(std::string& name);
+    const char* printTill(std::ostream& out, const char* data, const char* till);
+    int frameType(std::string& name, const Trie& f);
 
   public:
     FlameGraph(const char* title, Counter counter, double minwidth, bool reverse) :

src/flightRecorder.h

@@ -20,6 +20,7 @@
 #include "arch.h"
 #include "arguments.h"
 #include "event.h"
+#include "log.h"
 
 class Recording;
 
@@ -27,19 +28,27 @@ class FlightRecorder {
   private:
     Recording* _rec;
 
+    Error startMasterRecording(Arguments& args, const char* filename);
+    void stopMasterRecording();
+
   public:
     FlightRecorder() : _rec(NULL) {
     }
 
     Error start(Arguments& args, bool reset);
     void stop();
+    void flush();
+    size_t usedMemory();
+    bool timerTick(u64 wall_time);
 
-    bool active() {
+    bool active() const {
         return _rec != NULL;
     }
 
     void recordEvent(int lock_index, int tid, u32 call_trace_id,
-                     int event_type, Event* event, u64 counter);
+                     int event_type, Event* event);
+
+    void recordLog(LogLevel level, const char* message, size_t len);
 };
 
 #endif // _FLIGHTRECORDER_H

src/frameName.cpp

@@ -14,15 +14,20 @@
  * limitations under the License.
  */
 
-#include <cxxabi.h>
 #include <stdint.h>
 #include <stdlib.h>
 #include <string.h>
+#include "demangle.h"
 #include "frameName.h"
 #include "profiler.h"
 #include "vmStructs.h"
 
 
+static inline bool isDigit(char c) {
+    return c >= '0' && c <= '9';
+}
+
+
 Matcher::Matcher(const char* pattern) {
     if (pattern[0] == '*') {
         _type = MATCH_ENDS_WITH;
@@ -75,26 +80,42 @@ bool Matcher::matches(const char* s) {
 }
 
 
-FrameName::FrameName(Arguments& args, int style, Mutex& thread_names_lock, ThreadMap& thread_names) :
-    _cache(),
+JMethodCache FrameName::_cache;
+
+FrameName::FrameName(Arguments& args, int style, int epoch, Mutex& thread_names_lock, ThreadMap& thread_names) :
     _class_names(),
     _include(),
     _exclude(),
+    _str(),
     _style(style),
+    _cache_epoch((unsigned char)epoch),
+    _cache_max_age(args._mcache),
     _thread_names_lock(thread_names_lock),
     _thread_names(thread_names)
 {
     // Require printf to use standard C format regardless of system locale
     _saved_locale = uselocale(newlocale(LC_NUMERIC_MASK, "C", (locale_t)0));
-    memset(_buf, 0, sizeof(_buf));
 
     buildFilter(_include, args._buf, args._include);
     buildFilter(_exclude, args._buf, args._exclude);
 
-    Profiler::_instance.classMap()->collect(_class_names);
+    Profiler::instance()->classMap()->collect(_class_names);
 }
 
 FrameName::~FrameName() {
+    if (_cache_max_age == 0) {
+        _cache.clear();
+    } else {
+        // Remove stale methods from the cache, leave the fresh ones for the next profiling session
+        for (JMethodCache::iterator it = _cache.begin(); it != _cache.end(); ) {
+            if (_cache_epoch - (unsigned char)it->second[0] >= _cache_max_age) {
+                _cache.erase(it++);
+            } else {
+                ++it;
+            }
+        }
+    }
+
     freelocale(uselocale(_saved_locale));
 }
 
@@ -105,32 +126,47 @@ void FrameName::buildFilter(std::vector<Matcher>& vector, const char* base, int
     }
 }
 
-char* FrameName::truncate(char* name, int max_length) {
-    if (strlen(name) > max_length && max_length >= 4) {
-        strcpy(name + max_length - 4, "...)");
-    }
-    return name;
-}
+const char* FrameName::decodeNativeSymbol(const char* name) {
+    const char* lib_name = (_style & STYLE_LIB_NAMES) ? Profiler::instance()->getLibraryName(name) : NULL;
 
-const char* FrameName::cppDemangle(const char* name) {
-    if (name != NULL && name[0] == '_' && name[1] == 'Z') {
-        int status;
-        char* demangled = abi::__cxa_demangle(name, NULL, NULL, &status);
+    if (name[0] == '_' && name[1] == 'Z') {
+        char* demangled = Demangle::demangle(name);
         if (demangled != NULL) {
-            strncpy(_buf, demangled, sizeof(_buf) - 1);
+            if (lib_name != NULL) {
+                _str.assign(lib_name).append("`").append(demangled);
+            } else {
+                _str.assign(demangled);
+            }
             free(demangled);
-            return _buf;
+            return _str.c_str();
         }
     }
-    return name;
+
+    if (lib_name != NULL) {
+        return _str.assign(lib_name).append("`").append(name).c_str();
+    } else {
+        return name;
+    }
 }
 
-char* FrameName::javaMethodName(jmethodID method) {
+const char* FrameName::typeSuffix(FrameTypeId type) {
+    if (_style & STYLE_ANNOTATE) {
+        switch (type) {
+            case FRAME_INTERPRETED:  return "_[0]";
+            case FRAME_JIT_COMPILED: return "_[j]";
+            case FRAME_INLINED:      return "_[i]";
+            case FRAME_C1_COMPILED:  return "_[1]";
+            default:                 return NULL;
+        }
+    }
+    return NULL;
+}
+
+void FrameName::javaMethodName(jmethodID method) {
     jclass method_class;
     char* class_name = NULL;
     char* method_name = NULL;
     char* method_sig = NULL;
-    char* result;
 
     jvmtiEnv* jvmti = VM::jvmti();
     jvmtiError err;
@@ -139,26 +175,28 @@ char* FrameName::javaMethodName(jmethodID method) {
         (err = jvmti->GetMethodDeclaringClass(method, &method_class)) == 0 &&
         (err = jvmti->GetClassSignature(method_class, &class_name, NULL)) == 0) {
         // Trim 'L' and ';' off the class descriptor like 'Ljava/lang/Object;'
-        result = javaClassName(class_name + 1, strlen(class_name) - 2, _style);
-        strcat(result, ".");
-        strcat(result, method_name);
-        if (_style & STYLE_SIGNATURES) strcat(result, truncate(method_sig, 255));
-        if (_style & STYLE_ANNOTATE) strcat(result, "_[j]");
+        javaClassName(class_name + 1, strlen(class_name) - 2, _style);
+        _str.append(".").append(method_name);
+        if (_style & STYLE_SIGNATURES) {
+            if (_style & STYLE_NO_SEMICOLON) {
+                for (char* s = method_sig; *s; s++) {
+                    if (*s == ';') *s = '|';
+                }
+            }
+            _str.append(method_sig);
+        }
     } else {
-        snprintf(_buf, sizeof(_buf) - 1, "[jvmtiError %d]", err);
-        result = _buf;
+        char buf[32];
+        snprintf(buf, sizeof(buf), "[jvmtiError %d]", err);
+        _str.assign(buf);
     }
 
     jvmti->Deallocate((unsigned char*)class_name);
     jvmti->Deallocate((unsigned char*)method_sig);
     jvmti->Deallocate((unsigned char*)method_name);
-
-    return result;
 }
 
-char* FrameName::javaClassName(const char* symbol, int length, int style) {
-    char* result = _buf;
-
+void FrameName::javaClassName(const char* symbol, size_t length, int style) {
     int array_dimension = 0;
     while (*symbol == '[') {
         array_dimension++;
@@ -166,42 +204,40 @@ char* FrameName::javaClassName(const char* symbol, int length, int style) {
     }
 
     if (array_dimension == 0) {
-        strncpy(result, symbol, length);
-        result[length] = 0;
+        _str.assign(symbol, length);
     } else {
         switch (*symbol) {
-            case 'B': strcpy(result, "byte");    break;
-            case 'C': strcpy(result, "char");    break;
-            case 'I': strcpy(result, "int");     break;
-            case 'J': strcpy(result, "long");    break;
-            case 'S': strcpy(result, "short");   break;
-            case 'Z': strcpy(result, "boolean"); break;
-            case 'F': strcpy(result, "float");   break;
-            case 'D': strcpy(result, "double");  break;
-            default:
-                length -= array_dimension + 2;
-                strncpy(result, symbol + 1, length);
-                result[length] = 0;
+            case 'B': _str.assign("byte");    break;
+            case 'C': _str.assign("char");    break;
+            case 'I': _str.assign("int");     break;
+            case 'J': _str.assign("long");    break;
+            case 'S': _str.assign("short");   break;
+            case 'Z': _str.assign("boolean"); break;
+            case 'F': _str.assign("float");   break;
+            case 'D': _str.assign("double");  break;
+            default:  _str.assign(symbol + 1, length - array_dimension - 2);
         }
 
         do {
-            strcat(result, "[]");
+            _str += "[]";
         } while (--array_dimension > 0);
     }
 
     if (style & STYLE_SIMPLE) {
-        for (char* s = result; *s; s++) {
-            if (*s == '/') result = s + 1;
+        size_t start = 0;
+        size_t size = _str.size();
+        for (size_t i = 0; i < size; i++) {
+            if (_str[i] == '/' && !isDigit(_str[i + 1])) start = i + 1;
         }
+        _str.erase(0, start);
     }
 
     if (style & STYLE_DOTTED) {
-        for (char* s = result; *s; s++) {
-            if (*s == '/') *s = '.';
+        size_t size = _str.size();
+        for (size_t i = 0; i < size; i++) {
+            if (_str[i] == '/' && !isDigit(_str[i + 1])) _str[i] = '.';
         }
     }
-
-    return result;
 }
 
 const char* FrameName::name(ASGCT_CallFrame& frame, bool for_matching) {
@@ -211,18 +247,18 @@ const char* FrameName::name(ASGCT_CallFrame& frame, bool for_matching) {
 
     switch (frame.bci) {
         case BCI_NATIVE_FRAME:
-            return cppDemangle((const char*)frame.method_id);
+            return decodeNativeSymbol((const char*)frame.method_id);
 
         case BCI_ALLOC:
         case BCI_ALLOC_OUTSIDE_TLAB:
         case BCI_LOCK:
         case BCI_PARK: {
             const char* symbol = _class_names[(uintptr_t)frame.method_id];
-            char* class_name = javaClassName(symbol, strlen(symbol), _style | STYLE_DOTTED);
+            javaClassName(symbol, strlen(symbol), _style | STYLE_DOTTED);
             if (!for_matching && !(_style & STYLE_DOTTED)) {
-                strcat(class_name, frame.bci == BCI_ALLOC_OUTSIDE_TLAB ? "_[k]" : "_[i]");
+                _str += frame.bci == BCI_ALLOC_OUTSIDE_TLAB ? "_[k]" : "_[i]";
             }
-            return class_name;
+            return _str.c_str();
         }
 
         case BCI_THREAD_ID: {
@@ -231,28 +267,38 @@ const char* FrameName::name(ASGCT_CallFrame& frame, bool for_matching) {
             ThreadMap::iterator it = _thread_names.find(tid);
             if (for_matching) {
                 return it != _thread_names.end() ? it->second.c_str() : "";
-            } else if (it != _thread_names.end()) {
-                snprintf(_buf, sizeof(_buf) - 1, "[%s tid=%d]", it->second.c_str(), tid);
-            } else {
-                snprintf(_buf, sizeof(_buf) - 1, "[tid=%d]", tid);
             }
-            return _buf;
+
+            char buf[32];
+            snprintf(buf, sizeof(buf), "tid=%d]", tid);
+            if (it != _thread_names.end()) {
+                return _str.assign("[").append(it->second).append(" ").append(buf).c_str();
+            } else {
+                return _str.assign("[").append(buf).c_str();
+            }
         }
 
-        case BCI_ERROR: {
-            snprintf(_buf, sizeof(_buf) - 1, "[%s]", (const char*)frame.method_id);
-            return _buf;
-        }
+        case BCI_ERROR:
+            return _str.assign("[").append((const char*)frame.method_id).append("]").c_str();
 
         default: {
+            const char* type_suffix = typeSuffix(FrameType::decode(frame.bci));
+
             JMethodCache::iterator it = _cache.lower_bound(frame.method_id);
             if (it != _cache.end() && it->first == frame.method_id) {
-                return it->second.c_str();
+                it->second[0] = _cache_epoch;
+                if (type_suffix != NULL) {
+                    return _str.assign(it->second, 1, std::string::npos).append(type_suffix).c_str();
+                }
+                return it->second.c_str() + 1;
             }
 
-            const char* newName = javaMethodName(frame.method_id);
-            _cache.insert(it, JMethodCache::value_type(frame.method_id, newName));
-            return newName;
+            javaMethodName(frame.method_id);
+            _cache.insert(it, JMethodCache::value_type(frame.method_id, std::string(1, _cache_epoch) + _str));
+            if (type_suffix != NULL) {
+                _str += type_suffix;
+            }
+            return _str.c_str();
         }
     }
 }

src/frameName.h

@@ -63,24 +63,27 @@ class Matcher {
 
 class FrameName {
   private:
-    JMethodCache _cache;
+    static JMethodCache _cache;
+
     ClassMap _class_names;
     std::vector<Matcher> _include;
     std::vector<Matcher> _exclude;
-    char _buf[800];  // must be large enough for class name + method name + method signature
+    std::string _str;
     int _style;
+    unsigned char _cache_epoch;
+    unsigned char _cache_max_age;
     Mutex& _thread_names_lock;
     ThreadMap& _thread_names;
     locale_t _saved_locale;
 
     void buildFilter(std::vector<Matcher>& vector, const char* base, int offset);
-    char* truncate(char* name, int max_length);
-    const char* cppDemangle(const char* name);
-    char* javaMethodName(jmethodID method);
-    char* javaClassName(const char* symbol, int length, int style);
+    const char* decodeNativeSymbol(const char* name);
+    const char* typeSuffix(FrameTypeId type);
+    void javaMethodName(jmethodID method);
+    void javaClassName(const char* symbol, size_t length, int style);
 
   public:
-    FrameName(Arguments& args, int style, Mutex& thread_names_lock, ThreadMap& thread_names);
+    FrameName(Arguments& args, int style, int epoch, Mutex& thread_names_lock, ThreadMap& thread_names);
     ~FrameName();
 
     const char* name(ASGCT_CallFrame& frame, bool for_matching = false);

src/helper/one/profiler/Instrument.java

@@ -0,0 +1,28 @@
+/*
+ * Copyright 2021 Andrei Pangin
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package one.profiler;
+
+/**
+ * Instrumentation helper for Java method profiling.
+ */
+public class Instrument {
+
+    private Instrument() {
+    }
+
+    public static native void recordSample();
+}

src/helper/one/profiler/JfrSync.java

@@ -0,0 +1,117 @@
+/*
+ * Copyright 2021 Andrei Pangin
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package one.profiler;
+
+import jdk.jfr.Configuration;
+import jdk.jfr.FlightRecorder;
+import jdk.jfr.FlightRecorderListener;
+import jdk.jfr.Recording;
+import jdk.jfr.RecordingState;
+
+import java.io.IOException;
+import java.nio.file.NoSuchFileException;
+import java.nio.file.Paths;
+import java.text.ParseException;
+
+/**
+ * Synchronize async-profiler recording with an existing JFR recording.
+ */
+class JfrSync implements FlightRecorderListener {
+    private static volatile Recording masterRecording;
+
+    private JfrSync() {
+    }
+
+    static {
+        FlightRecorder.addListener(new JfrSync());
+    }
+
+    @Override
+    public void recordingStateChanged(Recording recording) {
+        if (recording == masterRecording && recording.getState() == RecordingState.STOPPED) {
+            masterRecording = null;
+            stopProfiler();
+        }
+    }
+
+    public static void start(String fileName, String settings, int eventMask) throws IOException, ParseException {
+        Configuration config;
+        try {
+            config = Configuration.getConfiguration(settings);
+        } catch (NoSuchFileException e) {
+            config = Configuration.create(Paths.get(settings));
+        }
+
+        Recording recording = new Recording(config);
+        masterRecording = recording;
+
+        disableBuiltinEvents(recording, eventMask);
+
+        recording.setDestination(Paths.get(fileName));
+        recording.setToDisk(true);
+        recording.setDumpOnExit(true);
+        recording.start();
+    }
+
+    public static void stop() {
+        Recording recording = masterRecording;
+        if (recording != null) {
+            // Disable state change notification before stopping
+            masterRecording = null;
+            recording.stop();
+        }
+    }
+
+    private static void disableBuiltinEvents(Recording recording, int eventMask) {
+        if ((eventMask & 1) != 0) {
+            recording.disable("jdk.ExecutionSample");
+            recording.disable("jdk.NativeMethodSample");
+        }
+        if ((eventMask & 2) != 0) {
+            recording.disable("jdk.ObjectAllocationInNewTLAB");
+            recording.disable("jdk.ObjectAllocationOutsideTLAB");
+            recording.disable("jdk.ObjectAllocationSample");
+        }
+        if ((eventMask & 4) != 0) {
+            recording.disable("jdk.JavaMonitorEnter");
+            recording.disable("jdk.ThreadPark");
+        }
+
+        // Shifted JfrOption values
+        if ((eventMask & 0x10) != 0) {
+            recording.disable("jdk.OSInformation");
+            recording.disable("jdk.CPUInformation");
+            recording.disable("jdk.JVMInformation");
+        }
+        if ((eventMask & 0x20) != 0) {
+            recording.disable("jdk.InitialSystemProperty");
+        }
+        if ((eventMask & 0x40) != 0) {
+            recording.disable("jdk.NativeLibrary");
+        }
+        if ((eventMask & 0x80) != 0) {
+            recording.disable("jdk.CPULoad");
+        }
+    }
+
+    private static native void stopProfiler();
+
+    // JNI helper
+    static Integer box(int n) {
+        return n;
+    }
+}

src/helper/one/profiler/Server.java

@@ -0,0 +1,111 @@
+/*
+ * Copyright 2022 Andrei Pangin
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package one.profiler;
+
+import com.sun.net.httpserver.HttpExchange;
+import com.sun.net.httpserver.HttpHandler;
+import com.sun.net.httpserver.HttpServer;
+
+import java.io.IOException;
+import java.net.InetSocketAddress;
+import java.net.URI;
+import java.nio.charset.StandardCharsets;
+import java.util.concurrent.Executor;
+import java.util.concurrent.atomic.AtomicInteger;
+
+class Server extends Thread implements Executor, HttpHandler {
+    private static final String[] COMMANDS = "start,resume,stop,dump,check,status,meminfo,list,version".split(",");
+
+    private final HttpServer server;
+    private final AtomicInteger threadNum = new AtomicInteger();
+
+    private Server(String address) throws IOException {
+        super("Async-profiler Server");
+        setDaemon(true);
+
+        int p = address.lastIndexOf(':');
+        InetSocketAddress socketAddress = p >= 0
+                ? new InetSocketAddress(address.substring(0, p), Integer.parseInt(address.substring(p + 1)))
+                : new InetSocketAddress(Integer.parseInt(address));
+
+        server = HttpServer.create(socketAddress, 0);
+        server.createContext("/", this);
+        server.setExecutor(this);
+    }
+
+    public static void start(String address) throws IOException {
+        new Server(address).start();
+    }
+
+    @Override
+    public void run() {
+        server.start();
+    }
+
+    @Override
+    public void execute(Runnable command) {
+        Thread t = new Thread(command, "Async-profiler Request #" + threadNum.incrementAndGet());
+        t.setDaemon(false);
+        t.start();
+    }
+
+    @Override
+    public void handle(HttpExchange exchange) throws IOException {
+        try {
+            String command = getCommand(exchange.getRequestURI());
+            if (command == null) {
+                sendResponse(exchange, 404, "Unknown command");
+            } else {
+                String response = execute0(command);
+                sendResponse(exchange, 200, response);
+            }
+        } catch (IllegalArgumentException e) {
+            sendResponse(exchange, 400, e.getMessage());
+        } catch (Exception e) {
+            sendResponse(exchange, 500, e.getMessage());
+        } finally {
+            exchange.close();
+        }
+    }
+
+    private String getCommand(URI uri) {
+        String path = uri.getPath();
+        if (path.startsWith("/")) {
+            if ((path = path.substring(1)).isEmpty()) {
+                return "version=full";
+            }
+            for (String command : COMMANDS) {
+                if (path.startsWith(command)) {
+                    String query = uri.getQuery();
+                    return query == null ? path : path + ',' + query.replace('&', ',');
+                }
+            }
+        }
+        return null;
+    }
+
+    private void sendResponse(HttpExchange exchange, int code, String body) throws IOException {
+        String contentType = body.startsWith("<!DOCTYPE html>") ? "text/html; charset=utf-8" : "text/plain";
+        exchange.getResponseHeaders().add("Content-Type", contentType);
+
+        byte[] bodyBytes = body.getBytes(StandardCharsets.UTF_8);
+        exchange.sendResponseHeaders(code, bodyBytes.length);
+        exchange.getResponseBody().write(bodyBytes);
+    }
+
+    private native String execute0(String command) throws IllegalArgumentException, IllegalStateException, IOException;
+}

src/incbin.h

@@ -0,0 +1,43 @@
+/*
+ * Copyright 2022 Andrei Pangin
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef _INCBIN_H
+#define _INCBIN_H
+
+#ifdef __APPLE__
+#  define INCBIN_SECTION ".const_data"
+#  define INCBIN_SYMBOL  "_"
+#else
+#  define INCBIN_SECTION ".section \".rodata\", \"a\", @progbits"
+#  define INCBIN_SYMBOL
+#endif
+
+#define INCBIN(NAME, FILE) \
+    extern const char NAME[];\
+    extern const char NAME##_END[];\
+    asm(INCBIN_SECTION "\n"\
+        ".global " INCBIN_SYMBOL #NAME "\n"\
+        INCBIN_SYMBOL #NAME ":\n"\
+        ".incbin \"" FILE "\"\n"\
+        ".global " INCBIN_SYMBOL #NAME "_END\n"\
+        INCBIN_SYMBOL #NAME "_END:\n"\
+        ".byte 0x00\n"\
+        ".previous\n"\
+    );
+
+#define INCBIN_SIZEOF(NAME) (NAME##_END - NAME)
+
+#endif // _INCBIN_H

src/instrument.cpp

@@ -18,34 +18,14 @@
 #include <stdlib.h>
 #include <string.h>
 #include "arch.h"
+#include "incbin.h"
 #include "os.h"
 #include "profiler.h"
 #include "vmEntry.h"
 #include "instrument.h"
 
 
-// A class with a single native recordSample() method
-static const char INSTRUMENT_CLASS[] =
-    "\xCA\xFE\xBA\xBE"                     // magic
-    "\x00\x00\x00\x32"                     // version: 50
-    "\x00\x07"                             // constant_pool_count: 7
-    "\x07\x00\x02"                         //   #1 = CONSTANT_Class: #2
-    "\x01\x00\x17one/profiler/Instrument"  //   #2 = CONSTANT_Utf8: "one/profiler/Instrument"
-    "\x07\x00\x04"                         //   #3 = CONSTANT_Class: #4
-    "\x01\x00\x10java/lang/Object"         //   #4 = CONSTANT_Utf8: "java/lang/Object"
-    "\x01\x00\x0CrecordSample"             //   #5 = CONSTANT_Utf8: "recordSample"
-    "\x01\x00\x03()V"                      //   #6 = CONSTANT_Utf8: "()V"
-    "\x00\x21"                             // access_flags: public super
-    "\x00\x01"                             // this_class: #1
-    "\x00\x03"                             // super_class: #3
-    "\x00\x00"                             // interfaces_count: 0
-    "\x00\x00"                             // fields_count: 0
-    "\x00\x01"                             // methods_count: 1
-    "\x01\x09"                             //   access_flags: public static native
-    "\x00\x05"                             //   name_index: #5
-    "\x00\x06"                             //   descriptor_index: #6
-    "\x00\x00"                             //   attributes_count: 0
-    "\x00";                                // attributes_count: 0
+INCBIN(INSTRUMENT_CLASS, "one/profiler/Instrument.class")
 
 
 enum ConstantTag {
@@ -255,6 +235,7 @@ class BytecodeRewriter {
     void rewriteCode();
     void rewriteBytecodeTable(int data_len);
     void rewriteStackMapTable();
+    void rewriteVerificationTypeInfo();
     void rewriteAttributes(Scope scope);
     void rewriteMembers(Scope scope);
     bool rewriteClass();
@@ -315,7 +296,7 @@ void BytecodeRewriter::rewriteCode() {
     put32(code_length + EXTRA_BYTECODES);
 
     // invokestatic "one/profiler/Instrument.recordSample()V"
-    // nop after invoke helps to prepend StackMapTable without rewriting
+    // nop ensures that tableswitch/lookupswitch needs no realignment
     put8(0xb8);
     put16(_cpool_len);
     put8(0);
@@ -366,7 +347,53 @@ void BytecodeRewriter::rewriteStackMapTable() {
 
     // Prepend same_frame
     put8(EXTRA_BYTECODES - 1);
-    put(get(attribute_length - 2), attribute_length - 2);
+
+    for (int i = 0; i < number_of_entries; i++) {
+        u8 frame_type = get8();
+        put8(frame_type);
+
+        if (frame_type <= 63) {
+            // same_frame
+        } else if (frame_type <= 127) {
+            // same_locals_1_stack_item_frame
+            rewriteVerificationTypeInfo();
+        } else if (frame_type == 247) {
+            // same_locals_1_stack_item_frame_extended
+            put16(get16());
+            rewriteVerificationTypeInfo();
+        } else if (frame_type <= 251) {
+            // chop_frame or same_frame_extended
+            put16(get16());
+        } else if (frame_type <= 254) {
+            // append_frame
+            put16(get16());
+            for (int j = 0; j < frame_type - 251; j++) {
+                rewriteVerificationTypeInfo();
+            }
+        } else {
+            // full_frame
+            put16(get16());
+            u16 number_of_locals = get16();
+            put16(number_of_locals);
+            for (int j = 0; j < number_of_locals; j++) {
+                rewriteVerificationTypeInfo();
+            }
+            u16 number_of_stack_items = get16();
+            put16(number_of_stack_items);
+            for (int j = 0; j < number_of_stack_items; j++) {
+                rewriteVerificationTypeInfo();
+            }
+        }
+    }
+}
+
+void BytecodeRewriter::rewriteVerificationTypeInfo() {
+    u8 tag = get8();
+    put8(tag);
+    if (tag >= 7) {
+        // Adjust ITEM_Uninitialized offset
+        put16(tag == 8 ? EXTRA_BYTECODES + get16() : get16());
+    }
 }
 
 void BytecodeRewriter::rewriteAttributes(Scope scope) {
@@ -487,9 +514,9 @@ Error Instrument::check(Arguments& args) {
         JNIEnv* jni = VM::jni();
         const JNINativeMethod native_method = {(char*)"recordSample", (char*)"()V", (void*)recordSample};
 
-        jclass cls = jni->DefineClass(NULL, NULL, (const jbyte*)INSTRUMENT_CLASS, sizeof(INSTRUMENT_CLASS));
+        jclass cls = jni->DefineClass(NULL, NULL, (const jbyte*)INSTRUMENT_CLASS, INCBIN_SIZEOF(INSTRUMENT_CLASS));
         if (cls == NULL || jni->RegisterNatives(cls, &native_method, 1) != 0) {
-            jni->ExceptionClear();
+            jni->ExceptionDescribe();
             return Error("Could not load Instrument class");
         }
 
@@ -509,7 +536,7 @@ Error Instrument::start(Arguments& args) {
         return Error("interval must be positive");
     }
 
-    setupTargetClassAndMethod(args._event_desc);
+    setupTargetClassAndMethod(args._event);
     _interval = args._interval ? args._interval : 1;
     _calls = 0;
     _running = true;
@@ -588,6 +615,6 @@ void JNICALL Instrument::recordSample(JNIEnv* jni, jobject unused) {
 
     if (_interval <= 1 || ((atomicInc(_calls) + 1) % _interval) == 0) {
         ExecutionEvent event;
-        Profiler::_instance.recordSample(NULL, _interval, BCI_INSTRUMENT, &event);
+        Profiler::instance()->recordSample(NULL, _interval, BCI_INSTRUMENT, &event);
     }
 }

src/instrument.h

@@ -30,18 +30,14 @@ class Instrument : public Engine {
     static volatile bool _running;
 
   public:
-    const char* name() {
-        return "instrument";
+    const char* title() {
+        return "Java method profile";
     }
 
     const char* units() {
         return "calls";
     }
 
-    CStack cstack() {
-        return CSTACK_NO;
-    }
-
     Error check(Arguments& args);
     Error start(Arguments& args);
     void stop();

src/itimer.cpp

@@ -16,18 +16,32 @@
 
 #include <sys/time.h>
 #include "itimer.h"
+#include "j9StackTraces.h"
 #include "os.h"
 #include "profiler.h"
+#include "stackWalker.h"
 
 
 long ITimer::_interval;
+CStack ITimer::_cstack;
 
 
 void ITimer::signalHandler(int signo, siginfo_t* siginfo, void* ucontext) {
     if (!_enabled) return;
 
     ExecutionEvent event;
-    Profiler::_instance.recordSample(ucontext, _interval, 0, &event);
+    Profiler::instance()->recordSample(ucontext, _interval, 0, &event);
+}
+
+void ITimer::signalHandlerJ9(int signo, siginfo_t* siginfo, void* ucontext) {
+    if (!_enabled) return;
+
+    J9StackTraceNotification notif;
+    StackContext java_ctx;
+    notif.num_frames = _cstack == CSTACK_NO ? 0 : _cstack == CSTACK_DWARF
+        ? StackWalker::walkDwarf(ucontext, notif.addr, MAX_J9_NATIVE_FRAMES, &java_ctx)
+        : StackWalker::walkFP(ucontext, notif.addr, MAX_J9_NATIVE_FRAMES, &java_ctx);
+    J9StackTraces::checkpoint(_interval, &notif);
 }
 
 Error ITimer::check(Arguments& args) {
@@ -49,11 +63,21 @@ Error ITimer::start(Arguments& args) {
         return Error("interval must be positive");
     }
     _interval = args._interval ? args._interval : DEFAULT_INTERVAL;
+    _cstack = args._cstack;
 
-    OS::installSignalHandler(SIGPROF, signalHandler);
+    if (VM::isOpenJ9()) {
+        if (_cstack == CSTACK_DEFAULT) _cstack = CSTACK_DWARF;
+        OS::installSignalHandler(SIGPROF, signalHandlerJ9);
+        Error error = J9StackTraces::start(args);
+        if (error) {
+            return error;
+        }
+    } else {
+        OS::installSignalHandler(SIGPROF, signalHandler);
+    }
 
-    long sec = _interval / 1000000000;
-    long usec = (_interval % 1000000000) / 1000;
+    time_t sec = _interval / 1000000000;
+    suseconds_t usec = (_interval % 1000000000) / 1000;
     struct itimerval tv = {{sec, usec}, {sec, usec}};
     
     if (setitimer(ITIMER_PROF, &tv, NULL) != 0) {
@@ -66,4 +90,6 @@ Error ITimer::start(Arguments& args) {
 void ITimer::stop() {
     struct itimerval tv = {{0, 0}, {0, 0}};
     setitimer(ITIMER_PROF, &tv, NULL);
+
+    J9StackTraces::stop();
 }

src/itimer.h

@@ -24,12 +24,14 @@
 class ITimer : public Engine {
   private:
     static long _interval;
+    static CStack _cstack;
 
     static void signalHandler(int signo, siginfo_t* siginfo, void* ucontext);
+    static void signalHandlerJ9(int signo, siginfo_t* siginfo, void* ucontext);
 
   public:
-    const char* name() {
-        return "itimer";
+    const char* title() {
+        return "CPU profile";
     }
 
     const char* units() {

src/j9Ext.cpp

@@ -0,0 +1,71 @@
+/*
+ * Copyright 2022 Andrei Pangin
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "j9Ext.h"
+#include "j9ObjectSampler.h"
+#include <string.h>
+
+
+jvmtiEnv* J9Ext::_jvmti;
+
+void* (*J9Ext::_j9thread_self)() = NULL;
+
+jvmtiExtensionFunction J9Ext::_GetOSThreadID = NULL;
+jvmtiExtensionFunction J9Ext::_GetJ9vmThread = NULL;
+jvmtiExtensionFunction J9Ext::_GetStackTraceExtended = NULL;
+jvmtiExtensionFunction J9Ext::_GetAllStackTracesExtended = NULL;
+
+int J9Ext::InstrumentableObjectAlloc_id = -1;
+
+
+// Look for OpenJ9-specific JVM TI extension
+bool J9Ext::initialize(jvmtiEnv* jvmti, const void* j9thread_self) {
+    _jvmti = jvmti;
+    _j9thread_self = (void* (*)())j9thread_self;
+
+    jint ext_count;
+    jvmtiExtensionFunctionInfo* ext_functions;
+    if (jvmti->GetExtensionFunctions(&ext_count, &ext_functions) == 0) {
+        for (int i = 0; i < ext_count; i++) {
+            if (strcmp(ext_functions[i].id, "com.ibm.GetOSThreadID") == 0) {
+                _GetOSThreadID = ext_functions[i].func;
+            } else if (strcmp(ext_functions[i].id, "com.ibm.GetJ9vmThread") == 0) {
+                _GetJ9vmThread = ext_functions[i].func;
+            } else if (strcmp(ext_functions[i].id, "com.ibm.GetStackTraceExtended") == 0) {
+                _GetStackTraceExtended = ext_functions[i].func;
+            } else if (strcmp(ext_functions[i].id, "com.ibm.GetAllStackTracesExtended") == 0) {
+                _GetAllStackTracesExtended = ext_functions[i].func;
+            }
+        }
+       jvmti->Deallocate((unsigned char*)ext_functions);
+    }
+
+    jvmtiExtensionEventInfo* ext_events;
+    if (jvmti->GetExtensionEvents(&ext_count, &ext_events) == 0) {
+        for (int i = 0; i < ext_count; i++) {
+            if (strcmp(ext_events[i].id, "com.ibm.InstrumentableObjectAlloc") == 0) {
+                InstrumentableObjectAlloc_id = ext_events[i].extension_event_index;
+                // If we don't set a callback now, we won't be able to enable it later in runtime
+                jvmti->SetExtensionEventCallback(InstrumentableObjectAlloc_id, (jvmtiExtensionEvent)J9ObjectSampler::JavaObjectAlloc);
+                jvmti->SetExtensionEventCallback(InstrumentableObjectAlloc_id, NULL);
+                break;
+            }
+        }
+       jvmti->Deallocate((unsigned char*)ext_events);
+    }
+
+    return _GetOSThreadID != NULL && _GetStackTraceExtended != NULL && _GetAllStackTracesExtended != NULL;
+}

src/j9Ext.h

@@ -0,0 +1,91 @@
+/*
+ * Copyright 2022 Andrei Pangin
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef _J9EXT_H
+#define _J9EXT_H
+
+#include <jvmti.h>
+
+
+#define JVMTI_EXT(f, ...)  ((jvmtiError (*)(jvmtiEnv*, __VA_ARGS__))f)
+
+struct jvmtiFrameInfoExtended {
+    jmethodID method;
+    jlocation location;
+    jlocation machinepc;
+    jint type;
+    void* native_frame_address;
+};
+
+struct jvmtiStackInfoExtended {
+    jthread thread;
+    jint state;
+    jvmtiFrameInfoExtended* frame_buffer;
+    jint frame_count;
+};
+
+enum {
+    SHOW_COMPILED_FRAMES = 4,
+    SHOW_INLINED_FRAMES = 8
+};
+
+
+class J9Ext {
+  private:
+    static jvmtiEnv* _jvmti;
+
+    static void* (*_j9thread_self)();
+
+    static jvmtiExtensionFunction _GetOSThreadID;
+    static jvmtiExtensionFunction _GetJ9vmThread;
+    static jvmtiExtensionFunction _GetStackTraceExtended;
+    static jvmtiExtensionFunction _GetAllStackTracesExtended;
+
+  public:
+    static bool initialize(jvmtiEnv* jvmti, const void* j9thread_self);
+
+    static int GetOSThreadID(jthread thread) {
+        jlong thread_id;
+        return JVMTI_EXT(_GetOSThreadID, jthread, jlong*)(_jvmti, thread, &thread_id) == 0 ? (int)thread_id : -1;
+    }
+
+    static JNIEnv* GetJ9vmThread(jthread thread) {
+        JNIEnv* result;
+        return JVMTI_EXT(_GetJ9vmThread, jthread, JNIEnv**)(_jvmti, thread, &result) == 0 ? result : NULL;
+    }
+
+    static jvmtiError GetStackTraceExtended(jthread thread, jint start_depth, jint max_frame_count,
+                                            void* frame_buffer, jint* count_ptr) {
+        return JVMTI_EXT(_GetStackTraceExtended, jint, jthread, jint, jint, void*, jint*)(
+            _jvmti, SHOW_COMPILED_FRAMES | SHOW_INLINED_FRAMES,
+            thread, start_depth, max_frame_count, frame_buffer, count_ptr);
+    }
+
+    static jvmtiError GetAllStackTracesExtended(jint max_frame_count, void** stack_info_ptr, jint* thread_count_ptr) {
+        return JVMTI_EXT(_GetAllStackTracesExtended, jint, jint, void**, jint*)(
+            _jvmti, SHOW_COMPILED_FRAMES | SHOW_INLINED_FRAMES,
+            max_frame_count, stack_info_ptr, thread_count_ptr);
+    }
+
+    static void* j9thread_self() {
+        return _j9thread_self != NULL ? _j9thread_self() : NULL;
+    }
+
+    static int InstrumentableObjectAlloc_id;
+};
+
+
+#endif // _J9EXT_H

src/j9ObjectSampler.cpp

@@ -0,0 +1,71 @@
+/*
+ * Copyright 2022 Andrei Pangin
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "j9ObjectSampler.h"
+#include "j9Ext.h"
+#include "vmEntry.h"
+
+
+void J9ObjectSampler::JavaObjectAlloc(jvmtiEnv* jvmti, JNIEnv* jni, jthread thread,
+                                      jobject object, jclass object_klass, jlong size) {
+    if (_enabled && updateCounter(_allocated_bytes, size, _interval)) {
+        recordAllocation(jvmti, jni, BCI_ALLOC, object, object_klass, size);
+    }
+}
+
+void J9ObjectSampler::VMObjectAlloc(jvmtiEnv* jvmti, JNIEnv* jni, jthread thread,
+                                    jobject object, jclass object_klass, jlong size) {
+    if (_enabled && updateCounter(_allocated_bytes, size, _interval)) {
+        recordAllocation(jvmti, jni, BCI_ALLOC_OUTSIDE_TLAB, object, object_klass, size);
+    }
+}
+
+Error J9ObjectSampler::check(Arguments& args) {
+    if (J9Ext::InstrumentableObjectAlloc_id < 0) {
+        return Error("InstrumentableObjectAlloc is not supported on this JVM");
+    }
+    return Error::OK;
+}
+
+Error J9ObjectSampler::start(Arguments& args) {
+    Error error = check(args);
+    if (error) {
+        return error;
+    }
+
+    _interval = args._alloc > 0 ? args._alloc : DEFAULT_ALLOC_INTERVAL;
+    _allocated_bytes = 0;
+
+    initLiveRefs(args._live);
+
+    jvmtiEnv* jvmti = VM::jvmti();
+    if (jvmti->SetExtensionEventCallback(J9Ext::InstrumentableObjectAlloc_id, (jvmtiExtensionEvent)JavaObjectAlloc) != 0) {
+        return Error("Could not enable InstrumentableObjectAlloc callback");
+    }
+    jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_OBJECT_ALLOC, NULL);
+    jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_GARBAGE_COLLECTION_START, NULL);
+
+    return Error::OK;
+}
+
+void J9ObjectSampler::stop() {
+    jvmtiEnv* jvmti = VM::jvmti();
+    jvmti->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_GARBAGE_COLLECTION_START, NULL);
+    jvmti->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_VM_OBJECT_ALLOC, NULL);
+    jvmti->SetExtensionEventCallback(J9Ext::InstrumentableObjectAlloc_id, NULL);
+
+    dumpLiveRefs();
+}

src/j9ObjectSampler.h

@@ -0,0 +1,36 @@
+/*
+ * Copyright 2022 Andrei Pangin
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef _J9OBJECTSAMPLER_H
+#define _J9OBJECTSAMPLER_H
+
+#include "objectSampler.h"
+
+
+class J9ObjectSampler : public ObjectSampler {
+  public:
+    Error check(Arguments& args);
+    Error start(Arguments& args);
+    void stop();
+
+    static void JNICALL JavaObjectAlloc(jvmtiEnv* jvmti, JNIEnv* jni, jthread thread,
+                                        jobject object, jclass object_klass, jlong size);
+
+    static void JNICALL VMObjectAlloc(jvmtiEnv* jvmti, JNIEnv* jni, jthread thread,
+                                      jobject object, jclass object_klass, jlong size);
+};
+
+#endif // _J9OBJECTSAMPLER_H

src/j9StackTraces.cpp

@@ -0,0 +1,186 @@
+/*
+ * Copyright 2021 Andrei Pangin
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <stdlib.h>
+#include <sys/time.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <map>
+#include "j9StackTraces.h"
+#include "j9Ext.h"
+#include "profiler.h"
+#include "perfEvents.h"
+
+
+enum {
+    J9_STOPPED = 0x40,
+    J9_HALT_THREAD_INSPECTION = 0x8000
+};
+
+class J9VMThread {
+  private:
+    uintptr_t _unused1[10];
+    uintptr_t _overflow_mark;
+    uintptr_t _unused2[8];
+    uintptr_t _flags;
+
+  public:
+    uintptr_t getAndSetFlag(uintptr_t flag) {
+        return __sync_fetch_and_or(&_flags, flag);
+    }
+
+    void clearFlag(uintptr_t flag) {
+        __sync_fetch_and_and(&_flags, ~flag);
+    }
+
+    void setOverflowMark() {
+        __atomic_store_n(&_overflow_mark, (uintptr_t)-1, __ATOMIC_RELEASE);
+    }
+};
+
+
+pthread_t J9StackTraces::_thread = 0;
+int J9StackTraces::_max_stack_depth;
+int J9StackTraces::_pipe[2];
+
+static JNIEnv* _self_env = NULL;
+
+
+Error J9StackTraces::start(Arguments& args) {
+    _max_stack_depth = args._jstackdepth; 
+
+    if (pipe(_pipe) != 0) {
+        return Error("Failed to create pipe");
+    }
+    fcntl(_pipe[1], F_SETFL, O_NONBLOCK);
+
+    if (pthread_create(&_thread, NULL, threadEntry, NULL) != 0) {
+        close(_pipe[0]);
+        close(_pipe[1]);
+        return Error("Unable to create sampler thread");
+    }
+
+    return Error::OK;
+}
+
+void J9StackTraces::stop() {
+    if (_thread != 0) {
+        close(_pipe[1]);
+        pthread_join(_thread, NULL);
+        close(_pipe[0]);
+        _thread = 0;
+    }
+}
+
+void J9StackTraces::timerLoop() {
+    JNIEnv* jni = VM::attachThread("Async-profiler Sampler");
+    __atomic_store_n(&_self_env, jni, __ATOMIC_RELEASE);
+
+    jni->PushLocalFrame(64);
+
+    jvmtiEnv* jvmti = VM::jvmti();
+    char notification_buf[65536];
+    std::map<void*, jthread> known_threads;
+
+    int max_frames = _max_stack_depth + MAX_J9_NATIVE_FRAMES + RESERVED_FRAMES;
+    ASGCT_CallFrame* frames = (ASGCT_CallFrame*)malloc(max_frames * sizeof(ASGCT_CallFrame));
+    jvmtiFrameInfoExtended* jvmti_frames = (jvmtiFrameInfoExtended*)malloc(max_frames * sizeof(jvmtiFrameInfoExtended));
+
+    while (true) {
+        ssize_t bytes = read(_pipe[0], notification_buf, sizeof(notification_buf));
+        if (bytes <= 0) {
+            if (bytes < 0 && errno == EAGAIN) {
+                continue;
+            }
+            break;
+        }
+
+        ssize_t ptr = 0;
+        while (ptr < bytes) {
+            J9StackTraceNotification* notif = (J9StackTraceNotification*)(notification_buf + ptr);
+
+            jthread thread = known_threads[notif->env];
+            jint num_jvmti_frames;
+            if (thread == NULL || J9Ext::GetStackTraceExtended(thread, 0, _max_stack_depth, jvmti_frames, &num_jvmti_frames) != 0) {
+                jni->PopLocalFrame(NULL);
+                jni->PushLocalFrame(64);
+
+                jint thread_count;
+                jthread* threads;
+                if (jvmti->GetAllThreads(&thread_count, &threads) == 0) {
+                    known_threads.clear();
+                    for (jint i = 0; i < thread_count; i++) {
+                        known_threads[J9Ext::GetJ9vmThread(threads[i])] = threads[i];
+                    }
+                    jvmti->Deallocate((unsigned char*)threads);
+                }
+
+                if ((thread = known_threads[notif->env]) == NULL ||
+                    J9Ext::GetStackTraceExtended(thread, 0, _max_stack_depth, jvmti_frames, &num_jvmti_frames) != 0) {
+                    continue;
+                }
+            }
+
+            int num_frames = Profiler::instance()->convertNativeTrace(notif->num_frames, notif->addr, frames);
+
+            for (int j = 0; j < num_jvmti_frames; j++) {
+                frames[num_frames].method_id = jvmti_frames[j].method;
+                frames[num_frames].bci = FrameType::encode(jvmti_frames[j].type, jvmti_frames[j].location);
+                num_frames++;
+            }
+
+            int tid = J9Ext::GetOSThreadID(thread);
+            ExecutionEvent event;
+            Profiler::instance()->recordExternalSample(notif->counter, tid, 0, &event, num_frames, frames);
+
+            ptr += notif->size();
+        }
+    }
+
+    free(jvmti_frames);
+    free(frames);
+
+    __atomic_store_n(&_self_env, NULL, __ATOMIC_RELEASE);
+    VM::detachThread();
+}
+
+void J9StackTraces::checkpoint(u64 counter, J9StackTraceNotification* notif) {
+    JNIEnv* self_env = __atomic_load_n(&_self_env, __ATOMIC_ACQUIRE);
+    if (self_env == NULL) {
+        // Sampler thread is not ready
+        return;
+    }
+
+    JNIEnv* env = VM::jni();
+    if (env != NULL && env != self_env) {
+        J9VMThread* vm_thread = (J9VMThread*)env;
+        uintptr_t flags = vm_thread->getAndSetFlag(J9_HALT_THREAD_INSPECTION);
+        if (flags & J9_HALT_THREAD_INSPECTION) {
+            // Thread is already scheduled for inspection, no need to notify again
+            return;
+        } else if (!(flags & J9_STOPPED)) {
+            vm_thread->setOverflowMark();
+            notif->env = env;
+            notif->counter = counter;
+            if (write(_pipe[1], notif, notif->size()) > 0) {
+                return;
+            }
+        }
+        // Something went wrong - rollback
+        vm_thread->clearFlag(J9_HALT_THREAD_INSPECTION);
+    }
+}

src/j9StackTraces.h

@@ -0,0 +1,60 @@
+/*
+ * Copyright 2021 Andrei Pangin
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef _J9STACKTRACES_H
+#define _J9STACKTRACES_H
+
+#include <pthread.h>
+#include "arch.h"
+#include "arguments.h"
+
+
+const int MAX_J9_NATIVE_FRAMES = 128;
+
+struct J9StackTraceNotification {
+    void* env;
+    u64 counter;
+    int num_frames;
+    int reserved;
+    const void* addr[MAX_J9_NATIVE_FRAMES];
+
+    size_t size() {
+        return sizeof(*this) - sizeof(this->addr) + num_frames * sizeof(const void*);
+    }
+};
+
+
+class J9StackTraces {
+  private:
+    static pthread_t _thread;
+    static int _max_stack_depth;
+    static int _pipe[2];
+
+    static void* threadEntry(void* unused) {
+        timerLoop();
+        return NULL;
+    }
+
+    static void timerLoop();
+
+  public:
+    static Error start(Arguments& args);
+    static void stop();
+
+    static void checkpoint(u64 counter, J9StackTraceNotification* notif);
+};
+
+#endif // _J9STACKTRACES_H

src/j9WallClock.cpp

@@ -0,0 +1,86 @@
+/*
+ * Copyright 2021 Andrei Pangin
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <stdlib.h>
+#include "j9WallClock.h"
+#include "j9Ext.h"
+#include "profiler.h"
+
+
+long J9WallClock::_interval;
+
+Error J9WallClock::start(Arguments& args) {
+    _interval = args._interval ? args._interval : DEFAULT_INTERVAL * 5;
+    _max_stack_depth = args._jstackdepth;
+
+    _running = true;
+
+    if (pthread_create(&_thread, NULL, threadEntry, this) != 0) {
+        return Error("Unable to create timer thread");
+    }
+
+    return Error::OK;
+}
+
+void J9WallClock::stop() {
+    _running = false;
+    pthread_kill(_thread, WAKEUP_SIGNAL);
+    pthread_join(_thread, NULL);
+}
+
+void J9WallClock::timerLoop() {
+    JNIEnv* jni = VM::attachThread("Async-profiler Sampler");
+    jvmtiEnv* jvmti = VM::jvmti();
+
+    int max_frames = _max_stack_depth + MAX_NATIVE_FRAMES + RESERVED_FRAMES;
+    ASGCT_CallFrame* frames = (ASGCT_CallFrame*)malloc(max_frames * sizeof(ASGCT_CallFrame));
+
+    while (_running) {
+        if (!_enabled) {
+            OS::sleep(_interval);
+            continue;
+        }
+
+        jni->PushLocalFrame(64);
+
+        jvmtiStackInfoExtended* stack_infos;
+        jint thread_count;
+        if (J9Ext::GetAllStackTracesExtended(_max_stack_depth, (void**)&stack_infos, &thread_count) == 0) {
+            for (int i = 0; i < thread_count; i++) {
+                jvmtiStackInfoExtended* si = &stack_infos[i];
+                for (int j = 0; j < si->frame_count; j++) {
+                    jvmtiFrameInfoExtended* fi = &si->frame_buffer[j];
+                    frames[j].method_id = fi->method;
+                    frames[j].bci = FrameType::encode(fi->type, fi->location);
+                }
+
+                int tid = J9Ext::GetOSThreadID(si->thread);
+                ExecutionEvent event;
+                event._thread_state = (si->state & JVMTI_THREAD_STATE_RUNNABLE) ? THREAD_RUNNING : THREAD_SLEEPING;
+                Profiler::instance()->recordExternalSample(_interval, tid, 0, &event, si->frame_count, frames);
+            }
+            jvmti->Deallocate((unsigned char*)stack_infos);
+        }
+
+        jni->PopLocalFrame(NULL);
+
+        OS::sleep(_interval);
+    }
+
+    free(frames);
+
+    VM::detachThread();
+}

src/j9WallClock.h

@@ -0,0 +1,52 @@
+/*
+ * Copyright 2021 Andrei Pangin
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef _J9WALLCLOCK_H
+#define _J9WALLCLOCK_H
+
+#include <pthread.h>
+#include "engine.h"
+
+
+class J9WallClock : public Engine {
+  private:
+    static long _interval;
+
+    int _max_stack_depth;
+    volatile bool _running;
+    pthread_t _thread;
+
+    static void* threadEntry(void* wall_clock) {
+        ((J9WallClock*)wall_clock)->timerLoop();
+        return NULL;
+    }
+
+    void timerLoop();
+
+  public:
+    const char* title() {
+        return "Wall clock profile";
+    }
+
+    const char* units() {
+        return "ns";
+    }
+
+    Error start(Arguments& args);
+    void stop();
+};
+
+#endif // _J9WALLCLOCK_H

src/jattach/jattach.c

@@ -1,5 +1,5 @@
 /*
- * Copyright 2016 Andrei Pangin
+ * Copyright 2021 Andrei Pangin
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,388 +16,35 @@
 
 #include <stdio.h>
 #include <stdlib.h>
-#include <string.h>
-#include <sys/types.h>
-#include <sys/stat.h>
-#include <sys/socket.h>
-#include <sys/un.h>
-#include <sys/syscall.h>
-#include <dirent.h>
-#include <errno.h>
-#include <fcntl.h>
 #include <signal.h>
-#include <time.h>
 #include <unistd.h>
-
-#define MAX_PATH 1024
-#define TMP_PATH (MAX_PATH - 64)
-
-static char tmp_path[TMP_PATH] = {0};
+#include "psutil.h"
 
 
-#ifdef __linux__
-
-int get_process_info(int pid, uid_t* uid, gid_t* gid, int* nspid) {
-    // Parse /proc/pid/status to find process credentials
-    char path[64];
-    snprintf(path, sizeof(path), "/proc/%d/status", pid);
-    FILE* status_file = fopen(path, "r");
-    if (status_file == NULL) {
-        return 0;
-    }
-
-    char* line = NULL;
-    size_t size;
-
-    while (getline(&line, &size, status_file) != -1) {
-        if (strncmp(line, "Uid:", 4) == 0) {
-            // Get the effective UID, which is the second value in the line
-            *uid = (uid_t)atoi(strchr(line + 5, '\t'));
-        } else if (strncmp(line, "Gid:", 4) == 0) {
-            // Get the effective GID, which is the second value in the line
-            *gid = (gid_t)atoi(strchr(line + 5, '\t'));
-        } else if (strncmp(line, "NStgid:", 7) == 0) {
-            // PID namespaces can be nested; the last one is the innermost one
-            *nspid = atoi(strrchr(line, '\t'));
-        }
-    }
-
-    free(line);
-    fclose(status_file);
-    return 1;
-}
-
-int get_tmp_path(int pid) {
-    // A process may have its own root path (when running in chroot environment)
-    char path[64];
-    snprintf(path, sizeof(path), "/proc/%d/root", pid);
-
-    // Append /tmp to the resolved root symlink
-    ssize_t path_size = readlink(path, tmp_path, sizeof(tmp_path) - 10);
-    strcpy(tmp_path + (path_size > 1 ? path_size : 0), "/tmp");
-    return 1;
-}
-
-int enter_mount_ns(int pid) {
-#ifdef __NR_setns
-    char path[128];
-    snprintf(path, sizeof(path), "/proc/%d/ns/mnt", pid);
-
-    struct stat oldns_stat, newns_stat;
-    if (stat("/proc/self/ns/mnt", &oldns_stat) == 0 && stat(path, &newns_stat) == 0) {
-        // Don't try to call setns() if we're in the same namespace already
-        if (oldns_stat.st_ino != newns_stat.st_ino) {
-            int newns = open(path, O_RDONLY);
-            if (newns < 0) {
-                return 0;
-            }
-
-            // Some ancient Linux distributions do not have setns() function
-            int result = syscall(__NR_setns, newns, 0);
-            close(newns);
-            return result < 0 ? 0 : 1;
-        }
-    }
-#endif // __NR_setns
-
-    return 1;
-}
-
-// The first line of /proc/pid/sched looks like
-// java (1234, #threads: 12)
-// where 1234 is the required host PID
-int sched_get_host_pid(const char* path) {
-    static char* line = NULL;
-    size_t size;
-    int result = -1;
-
-    FILE* sched_file = fopen(path, "r");
-    if (sched_file != NULL) {
-        if (getline(&line, &size, sched_file) != -1) {
-            char* c = strrchr(line, '(');
-            if (c != NULL) {
-                result = atoi(c + 1);
-            }
-        }
-        fclose(sched_file);
-    }
-
-    return result;
-}
-
-// Linux kernels < 4.1 do not export NStgid field in /proc/pid/status.
-// Fortunately, /proc/pid/sched in a container exposes a host PID,
-// so the idea is to scan all container PIDs to find which one matches the host PID.
-int alt_lookup_nspid(int pid) {
-    int namespace_differs = 0;
-    char path[300];
-    snprintf(path, sizeof(path), "/proc/%d/ns/pid", pid);
-
-    // Don't bother looking for container PID if we are already in the same PID namespace
-    struct stat oldns_stat, newns_stat;
-    if (stat("/proc/self/ns/pid", &oldns_stat) == 0 && stat(path, &newns_stat) == 0) {
-        if (oldns_stat.st_ino == newns_stat.st_ino) {
-            return pid;
-        }
-        namespace_differs = 1;
-    }
-
-    // Otherwise browse all PIDs in the namespace of the target process
-    // trying to find which one corresponds to the host PID
-    snprintf(path, sizeof(path), "/proc/%d/root/proc", pid);
-    DIR* dir = opendir(path);
-    if (dir != NULL) {
-        struct dirent* entry;
-        while ((entry = readdir(dir)) != NULL) {
-            if (entry->d_name[0] >= '1' && entry->d_name[0] <= '9') {
-                // Check if /proc/<container-pid>/sched points back to <host-pid>
-                snprintf(path, sizeof(path), "/proc/%d/root/proc/%s/sched", pid, entry->d_name);
-                if (sched_get_host_pid(path) == pid) {
-                    closedir(dir);
-                    return atoi(entry->d_name);
-                }
-            }
-        }
-        closedir(dir);
-    }
-
-    if (namespace_differs) {
-        printf("WARNING: couldn't find container pid of the target process\n");
-    }
-
-    return pid;
-}
-
-#elif defined(__APPLE__)
-
-#include <sys/sysctl.h>
-
-int get_process_info(int pid, uid_t* uid, gid_t* gid, int* nspid) {
-    int mib[4] = {CTL_KERN, KERN_PROC, KERN_PROC_PID, pid};
-    struct kinfo_proc info;
-    size_t len = sizeof(info);
-
-    if (sysctl(mib, 4, &info, &len, NULL, 0) < 0 || len <= 0) {
-        return 0;
-    }
-
-    *uid = info.kp_eproc.e_ucred.cr_uid;
-    *gid = info.kp_eproc.e_ucred.cr_gid;
-    *nspid = pid;
-    return 1;
-}
-
-// macOS has a secure per-user temporary directory
-int get_tmp_path(int pid) {
-    int path_size = confstr(_CS_DARWIN_USER_TEMP_DIR, tmp_path, sizeof(tmp_path));
-    return path_size > 0 && path_size <= sizeof(tmp_path);
-}
-
-// This is a Linux-specific API; nothing to do on macOS and FreeBSD
-int enter_mount_ns(int pid) {
-    return 1;
-}
-
-// Not used on macOS and FreeBSD
-int alt_lookup_nspid(int pid) {
-    return pid;
-}
-
-#else // __FreeBSD__
-
-#include <sys/sysctl.h>
-#include <sys/user.h>
-
-int get_process_info(int pid, uid_t* uid, gid_t* gid, int* nspid) {
-    int mib[4] = {CTL_KERN, KERN_PROC, KERN_PROC_PID, pid};
-    struct kinfo_proc info;
-    size_t len = sizeof(info);
-
-    if (sysctl(mib, 4, &info, &len, NULL, 0) < 0 || len <= 0) {
-        return 0;
-    }
-
-    *uid = info.ki_uid;
-    *gid = info.ki_groups[0];
-    *nspid = pid;
-    return 1;
-}
-
-// Use default /tmp path on FreeBSD
-int get_tmp_path(int pid) {
-    return 0;
-}
-
-// This is a Linux-specific API; nothing to do on macOS and FreeBSD
-int enter_mount_ns(int pid) {
-    return 1;
-}
-
-// Not used on macOS and FreeBSD
-int alt_lookup_nspid(int pid) {
-    return pid;
-}
-
-#endif
+extern int is_openj9_process(int pid);
+extern int jattach_openj9(int pid, int nspid, int argc, char** argv);
+extern int jattach_hotspot(int pid, int nspid, int argc, char** argv);
 
 
-// Check if remote JVM has already opened socket for Dynamic Attach
-static int check_socket(int pid) {
-    char path[MAX_PATH];
-    snprintf(path, sizeof(path), "%s/.java_pid%d", tmp_path, pid);
-
-    struct stat stats;
-    return stat(path, &stats) == 0 && S_ISSOCK(stats.st_mode);
-}
-
-// Check if a file is owned by current user
-static int check_file_owner(const char* path) {
-    struct stat stats;
-    if (stat(path, &stats) == 0 && stats.st_uid == geteuid()) {
-        return 1;
-    }
-
-    // Some mounted filesystems may change the ownership of the file.
-    // JVM will not trust such file, so it's better to remove it and try a different path
-    unlink(path);
-    return 0;
-}
-
-// Force remote JVM to start Attach listener.
-// HotSpot will start Attach listener in response to SIGQUIT if it sees .attach_pid file
-static int start_attach_mechanism(int pid, int nspid) {
-    char path[MAX_PATH];
-    snprintf(path, sizeof(path), "/proc/%d/cwd/.attach_pid%d", nspid, nspid);
-    
-    int fd = creat(path, 0660);
-    if (fd == -1 || (close(fd) == 0 && !check_file_owner(path))) {
-        // Failed to create attach trigger in current directory. Retry in /tmp
-        snprintf(path, sizeof(path), "%s/.attach_pid%d", tmp_path, nspid);
-        fd = creat(path, 0660);
-        if (fd == -1) {
-            return 0;
-        }
-        close(fd);
-    }
-    
-    // We have to still use the host namespace pid here for the kill() call
-    kill(pid, SIGQUIT);
-    
-    // Start with 20 ms sleep and increment delay each iteration
-    struct timespec ts = {0, 20000000};
-    int result;
-    do {
-        nanosleep(&ts, NULL);
-        result = check_socket(nspid);
-    } while (!result && (ts.tv_nsec += 20000000) < 300000000);
-
-    unlink(path);
-    return result;
-}
-
-// Connect to UNIX domain socket created by JVM for Dynamic Attach
-static int connect_socket(int pid) {
-    int fd = socket(PF_UNIX, SOCK_STREAM, 0);
-    if (fd == -1) {
-        return -1;
-    }
-    
-    struct sockaddr_un addr;
-    addr.sun_family = AF_UNIX;
-    int bytes = snprintf(addr.sun_path, sizeof(addr.sun_path), "%s/.java_pid%d", tmp_path, pid);
-    if (bytes >= sizeof(addr.sun_path)) {
-        addr.sun_path[sizeof(addr.sun_path) - 1] = 0;
-    }
-
-    if (connect(fd, (struct sockaddr*)&addr, sizeof(addr)) == -1) {
-        close(fd);
-        return -1;
-    }
-    return fd;
-}
-
-// Send command with arguments to socket
-static int write_command(int fd, int argc, char** argv) {
-    // Protocol version
-    if (write(fd, "1", 2) <= 0) {
-        return 0;
-    }
-
-    int i;
-    for (i = 0; i < 4; i++) {
-        const char* arg = i < argc ? argv[i] : "";
-        if (write(fd, arg, strlen(arg) + 1) <= 0) {
-            return 0;
-        }
-    }
-    return 1;
-}
-
-// Mirror response from remote JVM to stdout
-static int read_response(int fd) {
-    char buf[8192];
-    ssize_t bytes = read(fd, buf, sizeof(buf) - 1);
-    if (bytes <= 0) {
-        perror("Error reading response");
-        return 1;
-    }
-
-    // First line of response is the command result code
-    buf[bytes] = 0;
-    int result = atoi(buf);
-
-    do {
-        fwrite(buf, 1, bytes, stdout);
-        bytes = read(fd, buf, sizeof(buf));
-    } while (bytes > 0);
-
-    return result;
-}
-
-int main(int argc, char** argv) {
-    if (argc < 3) {
-        printf("jattach " JATTACH_VERSION " built on " __DATE__ "\n"
-               "Copyright 2018 Andrei Pangin\n"
-               "\n"
-               "Usage: jattach <pid> <cmd> [args ...]\n");
-        return 1;
-    }
-    
-    int pid = atoi(argv[1]);
-    if (pid == 0) {
-        perror("Invalid pid provided");
-        return 1;
-    }
-
+__attribute__((visibility("default")))
+int jattach(int pid, int argc, char** argv) {
     uid_t my_uid = geteuid();
     gid_t my_gid = getegid();
     uid_t target_uid = my_uid;
     gid_t target_gid = my_gid;
-    int nspid = -1;
-    if (!get_process_info(pid, &target_uid, &target_gid, &nspid)) {
+    int nspid;
+    if (get_process_info(pid, &target_uid, &target_gid, &nspid) < 0) {
         fprintf(stderr, "Process %d not found\n", pid);
         return 1;
     }
 
-    if (nspid < 0) {
-        nspid = alt_lookup_nspid(pid);
-    }
+    // Container support: switch to the target namespaces.
+    // Network and IPC namespaces are essential for OpenJ9 connection.
+    enter_ns(pid, "net");
+    enter_ns(pid, "ipc");
+    int mnt_changed = enter_ns(pid, "mnt");
 
-    // Get attach socket path of the target process (usually /tmp)
-    char* jattach_path = getenv("JATTACH_PATH");
-    if (jattach_path != NULL && strlen(jattach_path) < TMP_PATH) {
-        strcpy(tmp_path, jattach_path);
-    } else {
-        // Make sure our /tmp and target /tmp is the same
-        if (!get_tmp_path(pid)) {
-            strcpy(tmp_path, "/tmp");
-        }
-        if (!enter_mount_ns(pid)) {
-            printf("WARNING: couldn't enter target process mnt namespace\n");
-        }
-    }
-
-    // Dynamic attach is allowed only for the clients with the same euid/egid.
+    // In HotSpot, dynamic attach is allowed only for the clients with the same euid/egid.
     // If we are running under root, switch to the required euid/egid automatically.
     if ((my_gid != target_gid && setegid(target_gid) != 0) ||
         (my_uid != target_uid && seteuid(target_uid) != 0)) {
@@ -405,33 +52,41 @@ int main(int argc, char** argv) {
         return 1;
     }
 
-    // Make write() return EPIPE instead of silent process termination
+    get_tmp_path(mnt_changed > 0 ? nspid : pid);
+
+    // Make write() return EPIPE instead of abnormal process termination
     signal(SIGPIPE, SIG_IGN);
 
-    if (!check_socket(nspid) && !start_attach_mechanism(pid, nspid)) {
-        perror("Could not start attach mechanism");
-        return 1;
+    if (is_openj9_process(nspid)) {
+        return jattach_openj9(pid, nspid, argc, argv);
+    } else {
+        return jattach_hotspot(pid, nspid, argc, argv);
     }
-
-    int fd = connect_socket(nspid);
-    if (fd == -1) {
-        perror("Could not connect to socket");
-        return 1;
-    }
-    
-    printf("Connected to remote JVM\n");
-    if (!write_command(fd, argc - 2, argv + 2)) {
-        perror("Error writing to socket");
-        close(fd);
-        return 1;
-    }
-
-    printf("Response code = ");
-    fflush(stdout);
-
-    int result = read_response(fd);
-    printf("\n");
-    close(fd);
-
-    return result;
 }
+
+#ifdef JATTACH_VERSION
+
+int main(int argc, char** argv) {
+    if (argc < 3) {
+        printf("jattach " JATTACH_VERSION " built on " __DATE__ "\n"
+               "Copyright 2021 Andrei Pangin\n"
+               "\n"
+               "Usage: jattach <pid> <cmd> [args ...]\n"
+               "\n"
+               "Commands:\n"
+               "    load  threaddump   dumpheap  setflag    properties\n"
+               "    jcmd  inspectheap  datadump  printflag  agentProperties\n"
+               );
+        return 1;
+    }
+
+    int pid = atoi(argv[1]);
+    if (pid <= 0) {
+        fprintf(stderr, "%s is not a valid process ID\n", argv[1]);
+        return 1;
+    }
+
+    return jattach(pid, argc - 2, argv + 2);
+}
+
+#endif // JATTACH_VERSION

src/jattach/jattach_hotspot.c

@@ -0,0 +1,184 @@
+/*
+ * Copyright 2021 Andrei Pangin
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/socket.h>
+#include <sys/stat.h>
+#include <sys/un.h>
+#include <fcntl.h>
+#include <signal.h>
+#include <time.h>
+#include <unistd.h>
+#include "psutil.h"
+
+
+// Check if remote JVM has already opened socket for Dynamic Attach
+static int check_socket(int pid) {
+    char path[MAX_PATH];
+    snprintf(path, sizeof(path), "%s/.java_pid%d", tmp_path, pid);
+
+    struct stat stats;
+    return stat(path, &stats) == 0 && S_ISSOCK(stats.st_mode) ? 0 : -1;
+}
+
+// Check if a file is owned by current user
+static uid_t get_file_owner(const char* path) {
+    struct stat stats;
+    return stat(path, &stats) == 0 ? stats.st_uid : (uid_t)-1;
+}
+
+// Force remote JVM to start Attach listener.
+// HotSpot will start Attach listener in response to SIGQUIT if it sees .attach_pid file
+static int start_attach_mechanism(int pid, int nspid) {
+    char path[MAX_PATH];
+    snprintf(path, sizeof(path), "/proc/%d/cwd/.attach_pid%d", nspid, nspid);
+
+    int fd = creat(path, 0660);
+    if (fd == -1 || (close(fd) == 0 && get_file_owner(path) != geteuid())) {
+        // Some mounted filesystems may change the ownership of the file.
+        // JVM will not trust such file, so it's better to remove it and try a different path
+        unlink(path);
+
+        // Failed to create attach trigger in current directory. Retry in /tmp
+        snprintf(path, sizeof(path), "%s/.attach_pid%d", tmp_path, nspid);
+        fd = creat(path, 0660);
+        if (fd == -1) {
+            return -1;
+        }
+        close(fd);
+    }
+
+    // We have to still use the host namespace pid here for the kill() call
+    kill(pid, SIGQUIT);
+
+    // Start with 20 ms sleep and increment delay each iteration. Total timeout is 6000 ms
+    struct timespec ts = {0, 20000000};
+    int result;
+    do {
+        nanosleep(&ts, NULL);
+        result = check_socket(nspid);
+    } while (result != 0 && (ts.tv_nsec += 20000000) < 500000000);
+
+    unlink(path);
+    return result;
+}
+
+// Connect to UNIX domain socket created by JVM for Dynamic Attach
+static int connect_socket(int pid) {
+    int fd = socket(PF_UNIX, SOCK_STREAM, 0);
+    if (fd == -1) {
+        return -1;
+    }
+
+    struct sockaddr_un addr;
+    addr.sun_family = AF_UNIX;
+
+    int bytes = snprintf(addr.sun_path, sizeof(addr.sun_path), "%s/.java_pid%d", tmp_path, pid);
+    if (bytes >= sizeof(addr.sun_path)) {
+        addr.sun_path[sizeof(addr.sun_path) - 1] = 0;
+    }
+
+    if (connect(fd, (struct sockaddr*)&addr, sizeof(addr)) == -1) {
+        close(fd);
+        return -1;
+    }
+    return fd;
+}
+
+// Send command with arguments to socket
+static int write_command(int fd, int argc, char** argv) {
+    // Protocol version
+    if (write(fd, "1", 2) <= 0) {
+        return -1;
+    }
+
+    int i;
+    for (i = 0; i < 4; i++) {
+        const char* arg = i < argc ? argv[i] : "";
+        if (write(fd, arg, strlen(arg) + 1) <= 0) {
+            return -1;
+        }
+    }
+    return 0;
+}
+
+// Mirror response from remote JVM to stdout
+static int read_response(int fd, int argc, char** argv) {
+    char buf[8192];
+    ssize_t bytes = read(fd, buf, sizeof(buf) - 1);
+    if (bytes == 0) {
+        fprintf(stderr, "Unexpected EOF reading response\n");
+        return 1;
+    } else if (bytes < 0) {
+        perror("Error reading response");
+        return 1;
+    }
+
+    // First line of response is the command result code
+    buf[bytes] = 0;
+    int result = atoi(buf);
+
+    // Special treatment of 'load' command
+    if (result == 0 && argc > 0 && strcmp(argv[0], "load") == 0) {
+        size_t total = bytes;
+        while (total < sizeof(buf) - 1 && (bytes = read(fd, buf + total, sizeof(buf) - 1 - total)) > 0) {
+            total += (size_t)bytes;
+        }
+        bytes = total;
+
+        // The second line is the result of 'load' command; since JDK 9 it starts from "return code: "
+        buf[bytes] = 0;
+        result = atoi(strncmp(buf + 2, "return code: ", 13) == 0 ? buf + 15 : buf + 2);
+    }
+
+    // Mirror JVM response to stdout
+    printf("JVM response code = ");
+    do {
+        fwrite(buf, 1, bytes, stdout);
+        bytes = read(fd, buf, sizeof(buf));
+    } while (bytes > 0);
+    printf("\n");
+
+    return result;
+}
+
+int jattach_hotspot(int pid, int nspid, int argc, char** argv) {
+    if (check_socket(nspid) != 0 && start_attach_mechanism(pid, nspid) != 0) {
+        perror("Could not start attach mechanism");
+        return 1;
+    }
+
+    int fd = connect_socket(nspid);
+    if (fd == -1) {
+        perror("Could not connect to socket");
+        return 1;
+    }
+
+    printf("Connected to remote JVM\n");
+
+    if (write_command(fd, argc, argv) != 0) {
+        perror("Error writing to socket");
+        close(fd);
+        return 1;
+    }
+
+    int result = read_response(fd, argc, argv);
+    close(fd);
+
+    return result;
+}

src/jattach/jattach_openj9.c

@@ -0,0 +1,444 @@
+/*
+ * Copyright 2021 Andrei Pangin
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/file.h>
+#include <sys/ipc.h>
+#include <sys/sem.h>
+#include <sys/socket.h>
+#include <sys/stat.h>
+#include <netinet/in.h>
+#include <dirent.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <time.h>
+#include <unistd.h>
+#include "psutil.h"
+
+
+#define MAX_NOTIF_FILES 256
+static int notif_lock[MAX_NOTIF_FILES];
+
+
+// Translate HotSpot command to OpenJ9 equivalent
+static void translate_command(char* buf, size_t bufsize, int argc, char** argv) {
+    const char* cmd = argv[0];
+
+    if (strcmp(cmd, "load") == 0 && argc >= 2) {
+        if (argc > 2 && strcmp(argv[2], "true") == 0) {
+            snprintf(buf, bufsize, "ATTACH_LOADAGENTPATH(%s,%s)", argv[1], argc > 3 ? argv[3] : "");
+        } else {
+            snprintf(buf, bufsize, "ATTACH_LOADAGENT(%s,%s)", argv[1], argc > 3 ? argv[3] : "");
+        }
+
+    } else if (strcmp(cmd, "jcmd") == 0) {
+        snprintf(buf, bufsize, "ATTACH_DIAGNOSTICS:%s,%s", argc > 1 ? argv[1] : "help", argc > 2 ? argv[2] : "");
+
+    } else if (strcmp(cmd, "threaddump") == 0) {
+        snprintf(buf, bufsize, "ATTACH_DIAGNOSTICS:Thread.print,%s", argc > 1 ? argv[1] : "");
+
+    } else if (strcmp(cmd, "dumpheap") == 0) {
+        snprintf(buf, bufsize, "ATTACH_DIAGNOSTICS:Dump.heap,%s", argc > 1 ? argv[1] : "");
+
+    } else if (strcmp(cmd, "inspectheap") == 0) {
+        snprintf(buf, bufsize, "ATTACH_DIAGNOSTICS:GC.class_histogram,%s", argc > 1 ? argv[1] : "");
+
+    } else if (strcmp(cmd, "datadump") == 0) {
+        snprintf(buf, bufsize, "ATTACH_DIAGNOSTICS:Dump.java,%s", argc > 1 ? argv[1] : "");
+
+    } else if (strcmp(cmd, "properties") == 0) {
+        strcpy(buf, "ATTACH_GETSYSTEMPROPERTIES");
+
+    } else if (strcmp(cmd, "agentProperties") == 0) {
+        strcpy(buf, "ATTACH_GETAGENTPROPERTIES");
+
+    } else {
+        snprintf(buf, bufsize, "%s", cmd);
+    }
+
+    buf[bufsize - 1] = 0;
+}
+
+// Unescape a string and print it on stdout
+static void print_unescaped(char* str) {
+    char* p = strchr(str, '\n');
+    if (p != NULL) {
+        *p = 0;
+    }
+
+    while ((p = strchr(str, '\\')) != NULL) {
+        switch (p[1]) {
+            case 0:
+                break;
+            case 'f':
+                *p = '\f';
+                break;
+            case 'n':
+                *p = '\n';
+                break;
+            case 'r':
+                *p = '\r';
+                break;
+            case 't':
+                *p = '\t';
+                break;
+            default:
+                *p = p[1];
+        }
+        fwrite(str, 1, p - str + 1, stdout);
+        str = p + 2;
+    }
+
+    fwrite(str, 1, strlen(str), stdout);
+    printf("\n");
+}
+
+// Send command with arguments to socket
+static int write_command(int fd, const char* cmd) {
+    size_t len = strlen(cmd) + 1;
+    size_t off = 0;
+    while (off < len) {
+        ssize_t bytes = write(fd, cmd + off, len - off);
+        if (bytes <= 0) {
+            return -1;
+        }
+        off += bytes;
+    }
+    return 0;
+}
+
+// Mirror response from remote JVM to stdout
+static int read_response(int fd, const char* cmd) {
+    size_t size = 8192;
+    char* buf = malloc(size);
+
+    size_t off = 0;
+    while (buf != NULL) {
+        ssize_t bytes = read(fd, buf + off, size - off);
+        if (bytes == 0) {
+            fprintf(stderr, "Unexpected EOF reading response\n");
+            return 1;
+        } else if (bytes < 0) {
+            perror("Error reading response");
+            return 1;
+        }
+
+        off += bytes;
+        if (buf[off - 1] == 0) {
+            break;
+        }
+
+        if (off >= size) {
+            buf = realloc(buf, size *= 2);
+        }
+    }
+
+    if (buf == NULL) {
+        fprintf(stderr, "Failed to allocate memory for response\n");
+        return 1;
+    }
+
+    int result = 0;
+
+    if (strncmp(cmd, "ATTACH_LOADAGENT", 16) == 0) {
+        if (strncmp(buf, "ATTACH_ACK", 10) != 0) {
+            // AgentOnLoad error code comes right after AgentInitializationException
+            result = strncmp(buf, "ATTACH_ERR AgentInitializationException", 39) == 0 ? atoi(buf + 39) : -1;
+        }
+    } else if (strncmp(cmd, "ATTACH_DIAGNOSTICS:", 19) == 0) {
+        char* p = strstr(buf, "openj9_diagnostics.string_result=");
+        if (p != NULL) {
+            // The result of a diagnostic command is encoded in Java Properties format
+            print_unescaped(p + 33);
+            free(buf);
+            return result;
+        }
+    }
+
+    buf[off - 1] = '\n';
+    fwrite(buf, 1, off, stdout);
+
+    free(buf);
+    return result;
+}
+
+static void detach(int fd) {
+    if (write_command(fd, "ATTACH_DETACHED") != 0) {
+        return;
+    }
+
+    char buf[256];
+    ssize_t bytes;
+    do {
+        bytes = read(fd, buf, sizeof(buf));
+    } while (bytes > 0 && buf[bytes - 1] != 0);
+}
+
+static void close_with_errno(int fd) {
+    int saved_errno = errno;
+    close(fd);
+    errno = saved_errno;
+}
+
+static int acquire_lock(const char* subdir, const char* filename) {
+    char path[MAX_PATH];
+    snprintf(path, sizeof(path), "%s/.com_ibm_tools_attach/%s/%s", tmp_path, subdir, filename);
+
+    int lock_fd = open(path, O_WRONLY | O_CREAT, 0666);
+    if (lock_fd < 0) {
+        return -1;
+    }
+
+    if (flock(lock_fd, LOCK_EX) < 0) {
+        close_with_errno(lock_fd);
+        return -1;
+    }
+
+    return lock_fd;
+}
+
+static void release_lock(int lock_fd) {
+    flock(lock_fd, LOCK_UN);
+    close(lock_fd);
+}
+
+static int create_attach_socket(int* port) {
+    // Try IPv6 socket first, then fall back to IPv4
+    int s = socket(AF_INET6, SOCK_STREAM, 0);
+    if (s != -1) {
+        struct sockaddr_in6 addr = {AF_INET6, 0};
+        socklen_t addrlen = sizeof(addr);
+        if (bind(s, (struct sockaddr*)&addr, addrlen) == 0 && listen(s, 0) == 0
+                && getsockname(s, (struct sockaddr*)&addr, &addrlen) == 0) {
+            *port = ntohs(addr.sin6_port);
+            return s;
+        }
+    } else if ((s = socket(AF_INET, SOCK_STREAM, 0)) != -1) {
+        struct sockaddr_in addr = {AF_INET, 0};
+        socklen_t addrlen = sizeof(addr);
+        if (bind(s, (struct sockaddr*)&addr, addrlen) == 0 && listen(s, 0) == 0
+                && getsockname(s, (struct sockaddr*)&addr, &addrlen) == 0) {
+            *port = ntohs(addr.sin_port);
+            return s;
+        }
+    }
+
+    close_with_errno(s);
+    return -1;
+}
+
+static void close_attach_socket(int s, int pid) {
+    char path[MAX_PATH];
+    snprintf(path, sizeof(path), "%s/.com_ibm_tools_attach/%d/replyInfo", tmp_path, pid);
+    unlink(path);
+
+    close(s);
+}
+
+static unsigned long long random_key() {
+    unsigned long long key = time(NULL) * 0xc6a4a7935bd1e995ULL;
+
+    int fd = open("/dev/urandom", O_RDONLY);
+    if (fd >= 0) {
+        ssize_t r = read(fd, &key, sizeof(key));
+        (void)r;
+        close(fd);
+    }
+
+    return key;
+}
+
+static int write_reply_info(int pid, int port, unsigned long long key) {
+    char path[MAX_PATH];
+    snprintf(path, sizeof(path), "%s/.com_ibm_tools_attach/%d/replyInfo", tmp_path, pid);
+
+    int fd = open(path, O_WRONLY | O_CREAT | O_TRUNC, 0600);
+    if (fd < 0) {
+        return -1;
+    }
+
+    int chars = snprintf(path, sizeof(path), "%016llx\n%d\n", key, port);
+    ssize_t r = write(fd, path, chars);
+    (void)r;
+    close(fd);
+
+    return 0;
+}
+
+static int notify_semaphore(int value, int notif_count) {
+    char path[MAX_PATH];
+    snprintf(path, sizeof(path), "%s/.com_ibm_tools_attach/_notifier", tmp_path);
+
+    key_t sem_key = ftok(path, 0xa1);
+    int sem = semget(sem_key, 1, IPC_CREAT | 0666);
+    if (sem < 0) {
+        return -1;
+    }
+
+    struct sembuf op = {0, value, value < 0 ? IPC_NOWAIT : 0};
+    while (notif_count-- > 0) {
+        semop(sem, &op, 1);
+    }
+
+    return 0;
+}
+
+static int accept_client(int s, unsigned long long key) {
+    struct timeval tv = {5, 0};
+    setsockopt(s, SOL_SOCKET, SO_RCVTIMEO, &tv, sizeof(tv));
+
+    int client = accept(s, NULL, NULL);
+    if (client < 0) {
+        perror("JVM did not respond");
+        return -1;
+    }
+
+    char buf[35];
+    size_t off = 0;
+    while (off < sizeof(buf)) {
+        ssize_t bytes = recv(client, buf + off, sizeof(buf) - off, 0);
+        if (bytes <= 0) {
+            fprintf(stderr, "The JVM connection was prematurely closed\n");
+            close(client);
+            return -1;
+        }
+        off += bytes;
+    }
+
+    char expected[35];
+    snprintf(expected, sizeof(expected), "ATTACH_CONNECTED %016llx ", key);
+    if (memcmp(buf, expected, sizeof(expected) - 1) != 0) {
+        fprintf(stderr, "Unexpected JVM response\n");
+        close(client);
+        return -1;
+    }
+
+    // Reset the timeout, as the command execution may take arbitrary long time
+    struct timeval tv0 = {0, 0};
+    setsockopt(client, SOL_SOCKET, SO_RCVTIMEO, &tv0, sizeof(tv0));
+
+    return client;
+}
+
+static int lock_notification_files() {
+    int count = 0;
+
+    char path[MAX_PATH];
+    snprintf(path, sizeof(path), "%s/.com_ibm_tools_attach", tmp_path);
+
+    DIR* dir = opendir(path);
+    if (dir != NULL) {
+        struct dirent* entry;
+        while ((entry = readdir(dir)) != NULL && count < MAX_NOTIF_FILES) {
+            if (entry->d_name[0] >= '1' && entry->d_name[0] <= '9' &&
+                (entry->d_type == DT_DIR || entry->d_type == DT_UNKNOWN)) {
+                notif_lock[count++] = acquire_lock(entry->d_name, "attachNotificationSync");
+            }
+        }
+        closedir(dir);
+    }
+
+    return count;
+}
+
+static void unlock_notification_files(int count) {
+    int i;
+    for (i = 0; i < count; i++) {
+        if (notif_lock[i] >= 0) {
+            release_lock(notif_lock[i]);
+        }
+    }
+}
+
+int is_openj9_process(int pid) {
+    char path[MAX_PATH];
+    snprintf(path, sizeof(path), "%s/.com_ibm_tools_attach/%d/attachInfo", tmp_path, pid);
+
+    struct stat stats;
+    return stat(path, &stats) == 0;
+}
+
+int jattach_openj9(int pid, int nspid, int argc, char** argv) {
+    int attach_lock = acquire_lock("", "_attachlock");
+    if (attach_lock < 0) {
+        perror("Could not acquire attach lock");
+        return 1;
+    }
+
+    int notif_count = 0;
+    int port;
+    int s = create_attach_socket(&port);
+    if (s < 0) {
+        perror("Failed to listen to attach socket");
+        goto error;
+    }
+
+    unsigned long long key = random_key();
+    if (write_reply_info(nspid, port, key) != 0) {
+        perror("Could not write replyInfo");
+        goto error;
+    }
+
+    notif_count = lock_notification_files();
+    if (notify_semaphore(1, notif_count) != 0) {
+        perror("Could not notify semaphore");
+        goto error;
+    }
+
+    int fd = accept_client(s, key);
+    if (fd < 0) {
+        // The error message has been already printed
+        goto error;
+    }
+
+    close_attach_socket(s, nspid);
+    unlock_notification_files(notif_count);
+    notify_semaphore(-1, notif_count);
+    release_lock(attach_lock);
+
+    printf("Connected to remote JVM\n");
+
+    char cmd[8192];
+    translate_command(cmd, sizeof(cmd), argc, argv);
+
+    if (write_command(fd, cmd) != 0) {
+        perror("Error writing to socket");
+        close(fd);
+        return 1;
+    }
+
+    int result = read_response(fd, cmd);
+    if (result != 1) {
+        detach(fd);
+    }
+    close(fd);
+
+    return result;
+
+error:
+    if (s >= 0) {
+        close_attach_socket(s, nspid);
+    }
+    if (notif_count > 0) {
+        unlock_notification_files(notif_count);
+        notify_semaphore(-1, notif_count);
+    }
+    release_lock(attach_lock);
+
+    return 1;
+}

src/jattach/psutil.c

@@ -0,0 +1,243 @@
+/*
+ * Copyright 2021 Andrei Pangin
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <sys/syscall.h>
+#include <dirent.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include "psutil.h"
+
+
+// Less than MAX_PATH to leave some space for appending
+char tmp_path[MAX_PATH - 100];
+
+// Called just once to fill in tmp_path buffer
+void get_tmp_path(int pid) {
+    // Try user-provided alternative path first
+    const char* jattach_path = getenv("JATTACH_PATH");
+    if (jattach_path != NULL && strlen(jattach_path) < sizeof(tmp_path)) {
+        strcpy(tmp_path, jattach_path);
+        return;
+    }
+
+    if (get_tmp_path_r(pid, tmp_path, sizeof(tmp_path)) != 0) {
+        strcpy(tmp_path, "/tmp");
+    }
+}
+
+
+#ifdef __linux__
+
+// The first line of /proc/pid/sched looks like
+// java (1234, #threads: 12)
+// where 1234 is the host PID (before Linux 4.1)
+static int sched_get_host_pid(const char* path) {
+    static char* line = NULL;
+    size_t size;
+    int result = -1;
+
+    FILE* sched_file = fopen(path, "r");
+    if (sched_file != NULL) {
+        if (getline(&line, &size, sched_file) != -1) {
+            char* c = strrchr(line, '(');
+            if (c != NULL) {
+                result = atoi(c + 1);
+            }
+        }
+        fclose(sched_file);
+    }
+
+    return result;
+}
+
+// Linux kernels < 4.1 do not export NStgid field in /proc/pid/status.
+// Fortunately, /proc/pid/sched in a container exposes a host PID,
+// so the idea is to scan all container PIDs to find which one matches the host PID.
+static int alt_lookup_nspid(int pid) {
+    char path[300];
+    snprintf(path, sizeof(path), "/proc/%d/ns/pid", pid);
+
+    // Don't bother looking for container PID if we are already in the same PID namespace
+    struct stat oldns_stat, newns_stat;
+    if (stat("/proc/self/ns/pid", &oldns_stat) == 0 && stat(path, &newns_stat) == 0) {
+        if (oldns_stat.st_ino == newns_stat.st_ino) {
+            return pid;
+        }
+    }
+
+    // Otherwise browse all PIDs in the namespace of the target process
+    // trying to find which one corresponds to the host PID
+    snprintf(path, sizeof(path), "/proc/%d/root/proc", pid);
+    DIR* dir = opendir(path);
+    if (dir != NULL) {
+        struct dirent* entry;
+        while ((entry = readdir(dir)) != NULL) {
+            if (entry->d_name[0] >= '1' && entry->d_name[0] <= '9') {
+                // Check if /proc/<container-pid>/sched points back to <host-pid>
+                snprintf(path, sizeof(path), "/proc/%d/root/proc/%s/sched", pid, entry->d_name);
+                if (sched_get_host_pid(path) == pid) {
+                    pid = atoi(entry->d_name);
+                    break;
+                }
+            }
+        }
+        closedir(dir);
+    }
+
+    return pid;
+}
+
+int get_tmp_path_r(int pid, char* buf, size_t bufsize) {
+    if (snprintf(buf, bufsize, "/proc/%d/root/tmp", pid) >= bufsize) {
+        return -1;
+    }
+
+    // Check if the remote /tmp can be accessed via /proc/[pid]/root
+    struct stat stats;
+    return stat(buf, &stats);
+}
+
+int get_process_info(int pid, uid_t* uid, gid_t* gid, int* nspid) {
+    // Parse /proc/pid/status to find process credentials
+    char path[64];
+    snprintf(path, sizeof(path), "/proc/%d/status", pid);
+    FILE* status_file = fopen(path, "r");
+    if (status_file == NULL) {
+        return -1;
+    }
+
+    char* line = NULL;
+    size_t size;
+    int nspid_found = 0;
+
+    while (getline(&line, &size, status_file) != -1) {
+        if (strncmp(line, "Uid:", 4) == 0 && strtok(line + 4, "\t ") != NULL) {
+            // Get the effective UID, which is the second value in the line
+            *uid = (uid_t)atoi(strtok(NULL, "\t "));
+        } else if (strncmp(line, "Gid:", 4) == 0 && strtok(line + 4, "\t ") != NULL) {
+            // Get the effective GID, which is the second value in the line
+            *gid = (gid_t)atoi(strtok(NULL, "\t "));
+        } else if (strncmp(line, "NStgid:", 7) == 0) {
+            // PID namespaces can be nested; the last one is the innermost one
+            char* s;
+            for (s = strtok(line + 7, "\t "); s != NULL; s = strtok(NULL, "\t ")) {
+                *nspid = atoi(s);
+            }
+            nspid_found = 1;
+        }
+    }
+
+    free(line);
+    fclose(status_file);
+
+    if (!nspid_found) {
+        *nspid = alt_lookup_nspid(pid);
+    }
+
+    return 0;
+}
+
+int enter_ns(int pid, const char* type) {
+#ifdef __NR_setns
+    char path[64], selfpath[64];
+    snprintf(path, sizeof(path), "/proc/%d/ns/%s", pid, type);
+    snprintf(selfpath, sizeof(selfpath), "/proc/self/ns/%s", type);
+
+    struct stat oldns_stat, newns_stat;
+    if (stat(selfpath, &oldns_stat) == 0 && stat(path, &newns_stat) == 0) {
+        // Don't try to call setns() if we're in the same namespace already
+        if (oldns_stat.st_ino != newns_stat.st_ino) {
+            int newns = open(path, O_RDONLY);
+            if (newns < 0) {
+                return -1;
+            }
+
+            // Some ancient Linux distributions do not have setns() function
+            int result = syscall(__NR_setns, newns, 0);
+            close(newns);
+            return result < 0 ? -1 : 1;
+        }
+    }
+#endif // __NR_setns
+
+    return 0;
+}
+
+#elif defined(__APPLE__)
+
+#include <sys/sysctl.h>
+
+// macOS has a secure per-user temporary directory
+int get_tmp_path_r(int pid, char* buf, size_t bufsize) {
+    size_t path_size = confstr(_CS_DARWIN_USER_TEMP_DIR, buf, bufsize);
+    return path_size > 0 && path_size <= sizeof(tmp_path) ? 0 : -1;
+}
+
+int get_process_info(int pid, uid_t* uid, gid_t* gid, int* nspid) {
+    int mib[4] = {CTL_KERN, KERN_PROC, KERN_PROC_PID, pid};
+    struct kinfo_proc info;
+    size_t len = sizeof(info);
+
+    if (sysctl(mib, 4, &info, &len, NULL, 0) < 0 || len <= 0) {
+        return -1;
+    }
+
+    *uid = info.kp_eproc.e_ucred.cr_uid;
+    *gid = info.kp_eproc.e_ucred.cr_gid;
+    *nspid = pid;
+    return 0;
+}
+
+// This is a Linux-specific API; nothing to do on macOS and FreeBSD
+int enter_ns(int pid, const char* type) {
+    return 0;
+}
+
+#else // __FreeBSD__
+
+#include <sys/sysctl.h>
+#include <sys/user.h>
+
+// Use default /tmp path on FreeBSD
+int get_tmp_path_r(int pid, char* buf, size_t bufsize) {
+    return -1;
+}
+
+int get_process_info(int pid, uid_t* uid, gid_t* gid, int* nspid) {
+    int mib[4] = {CTL_KERN, KERN_PROC, KERN_PROC_PID, pid};
+    struct kinfo_proc info;
+    size_t len = sizeof(info);
+
+    if (sysctl(mib, 4, &info, &len, NULL, 0) < 0 || len <= 0) {
+        return -1;
+    }
+
+    *uid = info.ki_uid;
+    *gid = info.ki_groups[0];
+    *nspid = pid;
+    return 0;
+}
+
+// This is a Linux-specific API; nothing to do on macOS and FreeBSD
+int enter_ns(int pid, const char* type) {
+    return 0;
+}
+
+#endif

src/jattach/psutil.h

@@ -0,0 +1,46 @@
+/*
+ * Copyright 2021 Andrei Pangin
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef _PSUTIL_H
+#define _PSUTIL_H
+
+#include <sys/types.h>
+
+
+#define MAX_PATH 1024
+extern char tmp_path[];
+
+// Gets /tmp path of the specified process, as it can be accessed from the host.
+// The obtained path is stored in the global tmp_path buffer.
+void get_tmp_path(int pid);
+
+// The reentrant version of get_tmp_path.
+// Stores the process-specific temporary path into the provided buffer.
+// Returns 0 on success, -1 on failure.
+int get_tmp_path_r(int pid, char* buf, size_t bufsize);
+
+// Gets the owner uid/gid of the target process, and also its pid inside the container.
+// Returns 0 on success, -1 on failure.
+int get_process_info(int pid, uid_t* uid, gid_t* gid, int* nspid);
+
+// Tries to enter the namespace of the target process.
+// type of the namespace can be "mnt", "net", "pid", etc.
+// Returns 1, if the namespace has been successfully changed,
+//         0, if the target process is in the same namespace as the host,
+//        -1, if the attempt failed.
+int enter_ns(int pid, const char* type);
+
+#endif // _PSUTIL_H

src/javaApi.cpp

@@ -18,37 +18,55 @@
 #include <sstream>
 #include <errno.h>
 #include <string.h>
+#include "incbin.h"
 #include "javaApi.h"
-#include "arguments.h"
 #include "os.h"
 #include "profiler.h"
 #include "vmStructs.h"
 
 
-extern "C" JNIEXPORT void JNICALL
+INCBIN(SERVER_CLASS, "one/profiler/Server.class")
+
+
+static void throwNew(JNIEnv* env, const char* exception_class, const char* message) {
+    jclass cls = env->FindClass(exception_class);
+    if (cls != NULL) {
+        env->ThrowNew(cls, message);
+    }
+}
+
+
+extern "C" DLLEXPORT void JNICALL
 Java_one_profiler_AsyncProfiler_start0(JNIEnv* env, jobject unused, jstring event, jlong interval, jboolean reset) {
     Arguments args;
     const char* event_str = env->GetStringUTFChars(event, NULL);
-    args.addEvent(event_str); 
-    args._interval = interval;
-    Error error = Profiler::_instance.start(args, reset);
+    if (strcmp(event_str, EVENT_ALLOC) == 0) {
+        args._alloc = interval > 0 ? interval : 0;
+    } else if (strcmp(event_str, EVENT_LOCK) == 0) {
+        args._lock = interval > 0 ? interval : 0;
+    } else {
+        args._event = event_str;
+        args._interval = interval;
+    }
+
+    Error error = Profiler::instance()->start(args, reset);
     env->ReleaseStringUTFChars(event, event_str);
 
     if (error) {
-        JavaAPI::throwNew(env, "java/lang/IllegalStateException", error.message());
+        throwNew(env, "java/lang/IllegalStateException", error.message());
     }
 }
 
-extern "C" JNIEXPORT void JNICALL
+extern "C" DLLEXPORT void JNICALL
 Java_one_profiler_AsyncProfiler_stop0(JNIEnv* env, jobject unused) {
-    Error error = Profiler::_instance.stop();
+    Error error = Profiler::instance()->stop();
 
     if (error) {
-        JavaAPI::throwNew(env, "java/lang/IllegalStateException", error.message());
+        throwNew(env, "java/lang/IllegalStateException", error.message());
     }
 }
 
-extern "C" JNIEXPORT jstring JNICALL
+extern "C" DLLEXPORT jstring JNICALL
 Java_one_profiler_AsyncProfiler_execute0(JNIEnv* env, jobject unused, jstring command) {
     Arguments args;
     const char* command_str = env->GetStringUTFChars(command, NULL);
@@ -56,48 +74,54 @@ Java_one_profiler_AsyncProfiler_execute0(JNIEnv* env, jobject unused, jstring co
     env->ReleaseStringUTFChars(command, command_str);
 
     if (error) {
-        JavaAPI::throwNew(env, "java/lang/IllegalArgumentException", error.message());
+        throwNew(env, "java/lang/IllegalArgumentException", error.message());
         return NULL;
     }
 
-    if (args._file == NULL || args._output == OUTPUT_JFR) {
+    Log::open(args);
+
+    if (!args.hasOutputFile()) {
         std::ostringstream out;
-        Profiler::_instance.runInternal(args, out);
-        return env->NewStringUTF(out.str().c_str());
+        error = Profiler::instance()->runInternal(args, out);
+        if (!error) {
+            if (out.tellp() >= 0x3fffffff) {
+                throwNew(env, "java/lang/IllegalStateException", "Output exceeds string size limit");
+                return NULL;
+            }
+            return env->NewStringUTF(out.str().c_str());
+        }
     } else {
-        std::ofstream out(args._file, std::ios::out | std::ios::trunc);
-        if (out.is_open()) {
-            Profiler::_instance.runInternal(args, out);
-            out.close();
-            return env->NewStringUTF("OK");
-        } else {
-            JavaAPI::throwNew(env, "java/io/IOException", strerror(errno));
+        std::ofstream out(args.file(), std::ios::out | std::ios::trunc);
+        if (!out.is_open()) {
+            throwNew(env, "java/io/IOException", strerror(errno));
             return NULL;
         }
+        error = Profiler::instance()->runInternal(args, out);
+        out.close();
+        if (!error) {
+            return env->NewStringUTF("OK");
+        }
     }
+
+    throwNew(env, "java/lang/IllegalStateException", error.message());
+    return NULL;
 }
 
-extern "C" JNIEXPORT jlong JNICALL
+extern "C" DLLEXPORT jlong JNICALL
 Java_one_profiler_AsyncProfiler_getSamples(JNIEnv* env, jobject unused) {
-    return (jlong)Profiler::_instance.total_samples();
+    return (jlong)Profiler::instance()->total_samples();
 }
 
-extern "C" JNIEXPORT void JNICALL
+extern "C" DLLEXPORT void JNICALL
 Java_one_profiler_AsyncProfiler_filterThread0(JNIEnv* env, jobject unused, jthread thread, jboolean enable) {
     int thread_id;
     if (thread == NULL) {
         thread_id = OS::threadId();
-    } else if (VMThread::hasNativeId()) {
-        VMThread* vmThread = VMThread::fromJavaThread(env, thread);
-        if (vmThread == NULL) {
-            return;
-        }
-        thread_id = vmThread->osThreadId();
-    } else {
+    } else if ((thread_id = VMThread::nativeThreadId(env, thread)) < 0) {
         return;
     }
 
-    ThreadFilter* thread_filter = Profiler::_instance.threadFilter();
+    ThreadFilter* thread_filter = Profiler::instance()->threadFilter();
     if (enable) {
         thread_filter->add(thread_id);
     } else {
@@ -116,16 +140,11 @@ static const JNINativeMethod profiler_natives[] = {
     F(filterThread0, "(Ljava/lang/Thread;Z)V"),
 };
 
+static const JNINativeMethod* execute0 = &profiler_natives[2];
+
 #undef F
 
 
-void JavaAPI::throwNew(JNIEnv* env, const char* exception_class, const char* message) {
-    jclass cls = env->FindClass(exception_class);
-    if (cls != NULL) {
-        env->ThrowNew(cls, message);
-    }
-}
-
 // Since AsyncProfiler class can be renamed or moved to another package (shaded),
 // we look for the actual class in the stack trace.
 void JavaAPI::registerNatives(jvmtiEnv* jvmti, JNIEnv* jni) {
@@ -155,3 +174,23 @@ void JavaAPI::registerNatives(jvmtiEnv* jvmti, JNIEnv* jni) {
 
     jni->ExceptionClear();
 }
+
+bool JavaAPI::startHttpServer(jvmtiEnv* jvmti, JNIEnv* jni, const char* address) {
+    jclass handler = jni->FindClass("com/sun/net/httpserver/HttpHandler");
+    jobject loader;
+    if (handler != NULL && jvmti->GetClassLoader(handler, &loader) == 0) {
+        jclass cls = jni->DefineClass(NULL, loader, (const jbyte*)SERVER_CLASS, INCBIN_SIZEOF(SERVER_CLASS));
+        if (cls != NULL && jni->RegisterNatives(cls, execute0, 1) == 0) {
+            jmethodID method = jni->GetStaticMethodID(cls, "start", "(Ljava/lang/String;)V");
+            if (method != NULL) {
+                jni->CallStaticVoidMethod(cls, method, jni->NewStringUTF(address));
+                if (!jni->ExceptionCheck()) {
+                    return true;
+                }
+            }
+        }
+    }
+
+    jni->ExceptionDescribe();
+    return false;
+}

src/javaApi.h

@@ -22,8 +22,8 @@
 
 class JavaAPI {
   public:
-    static void throwNew(JNIEnv* env, const char* exception_class, const char* message);
     static void registerNatives(jvmtiEnv* jvmti, JNIEnv* jni);
+    static bool startHttpServer(jvmtiEnv* jvmti, JNIEnv* jni, const char* address);
 };
 
 #endif // _JAVAAPI_H

src/jfrMetadata.cpp

@@ -82,6 +82,9 @@ JfrMetadata::JfrMetadata() : Element("root") {
             << (type("jdk.types.Symbol", T_SYMBOL, "Symbol", true)
                 << field("string", T_STRING, "String"))
 
+            << (type("profiler.types.LogLevel", T_LOG_LEVEL, "Log Level", true)
+                << field("name", T_STRING, "Name"))
+
             << (type("jdk.ExecutionSample", T_EXECUTION_SAMPLE, "Method Profiling Sample")
                 << category("Java Virtual Machine", "Profiling")
                 << field("startTime", T_LONG, "Start Time", F_TIME_TICKS)
@@ -113,6 +116,7 @@ JfrMetadata::JfrMetadata() : Element("root") {
                 << field("eventThread", T_THREAD, "Event Thread", F_CPOOL)
                 << field("stackTrace", T_STACK_TRACE, "Stack Trace", F_CPOOL)
                 << field("monitorClass", T_CLASS, "Monitor Class", F_CPOOL)
+                << field("previousOwner", T_THREAD, "Previous Monitor Owner", F_CPOOL)
                 << field("address", T_LONG, "Monitor Address", F_ADDRESS))
 
             << (type("jdk.ThreadPark", T_THREAD_PARK, "Java Thread Park")
@@ -123,6 +127,7 @@ JfrMetadata::JfrMetadata() : Element("root") {
                 << field("stackTrace", T_STACK_TRACE, "Stack Trace", F_CPOOL)
                 << field("parkedClass", T_CLASS, "Class Parked On", F_CPOOL)
                 << field("timeout", T_LONG, "Park Timeout", F_DURATION_NANOS)
+                << field("until", T_LONG, "Park Until", F_TIME_MILLIS)
                 << field("address", T_LONG, "Address of Object Parked", F_ADDRESS))
 
             << (type("jdk.CPULoad", T_CPU_LOAD, "CPU Load")
@@ -132,7 +137,7 @@ JfrMetadata::JfrMetadata() : Element("root") {
                 << field("jvmSystem", T_FLOAT, "JVM System", F_PERCENTAGE)
                 << field("machineTotal", T_FLOAT, "Machine Total", F_PERCENTAGE))
 
-            << (type("jdk.ActiveRecording", T_ACTIVE_RECORDING, "Flight Recording")
+            << (type("jdk.ActiveRecording", T_ACTIVE_RECORDING, "Async-profiler Recording")
                 << category("Flight Recorder")
                 << field("startTime", T_LONG, "Start Time", F_TIME_TICKS)
                 << field("duration", T_LONG, "Duration", F_DURATION_TICKS)
@@ -145,11 +150,12 @@ JfrMetadata::JfrMetadata() : Element("root") {
                 << field("recordingStart", T_LONG, "Start Time", F_TIME_MILLIS)
                 << field("recordingDuration", T_LONG, "Recording Duration", F_DURATION_MILLIS))
 
-            << (type("jdk.ActiveSetting", T_ACTIVE_SETTING, "Recording Setting")
+            << (type("jdk.ActiveSetting", T_ACTIVE_SETTING, "Async-profiler Setting")
                 << category("Flight Recorder")
                 << field("startTime", T_LONG, "Start Time", F_TIME_TICKS)
                 << field("duration", T_LONG, "Duration", F_DURATION_TICKS)
                 << field("eventThread", T_THREAD, "Event Thread", F_CPOOL)
+                << field("stackTrace", T_STACK_TRACE, "Stack Trace", F_CPOOL)
                 << field("id", T_LONG, "Event Id")
                 << field("name", T_STRING, "Setting Name")
                 << field("value", T_STRING, "Setting Value"))
@@ -185,6 +191,28 @@ JfrMetadata::JfrMetadata() : Element("root") {
                 << field("key", T_STRING, "Key")
                 << field("value", T_STRING, "Value"))
 
+            << (type("jdk.NativeLibrary", T_NATIVE_LIBRARY, "Native Library")
+                << category("Java Virtual Machine", "Runtime")
+                << field("startTime", T_LONG, "Start Time", F_TIME_TICKS)
+                << field("name", T_STRING, "Name")
+                << field("baseAddress", T_LONG, "Base Address", F_ADDRESS)
+                << field("topAddress", T_LONG, "Top Address", F_ADDRESS))
+
+            << (type("profiler.Log", T_LOG, "Log Message")
+                << category("Profiler")
+                << field("startTime", T_LONG, "Start Time", F_TIME_TICKS)
+                << field("level", T_LOG_LEVEL, "Level", F_CPOOL)
+                << field("message", T_STRING, "Message"))
+
+            << (type("profiler.LiveObject", T_LIVE_OBJECT, "Live Object")
+                << category("Java Application")
+                << field("startTime", T_LONG, "Start Time", F_TIME_TICKS)
+                << field("eventThread", T_THREAD, "Event Thread", F_CPOOL)
+                << field("stackTrace", T_STACK_TRACE, "Stack Trace", F_CPOOL)
+                << field("objectClass", T_CLASS, "Object Class", F_CPOOL)
+                << field("allocationSize", T_LONG, "Allocation Size", F_BYTES)
+                << field("allocationTime", T_LONG, "Allocation Time", F_TIME_TICKS))
+
             << (type("jdk.jfr.Label", T_LABEL, NULL)
                 << field("value", T_STRING))
 

src/jfrMetadata.h

@@ -48,6 +48,7 @@ enum JfrType {
     T_METHOD = 28,
     T_PACKAGE = 29,
     T_SYMBOL = 30,
+    T_LOG_LEVEL = 31,
 
     T_EVENT = 100,
     T_EXECUTION_SAMPLE = 101,
@@ -62,6 +63,9 @@ enum JfrType {
     T_CPU_INFORMATION = 110,
     T_JVM_INFORMATION = 111,
     T_INITIAL_SYSTEM_PROPERTY = 112,
+    T_NATIVE_LIBRARY = 113,
+    T_LOG = 114,
+    T_LIVE_OBJECT = 115,
 
     T_ANNOTATION = 200,
     T_LABEL = 201,

src/jstack.cpp

@@ -1,71 +0,0 @@
-/*
- * Copyright 2021 Andrei Pangin
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-#include <signal.h>
-#include <time.h>
-#include "jstack.h"
-#include "profiler.h"
-
-
-// Wait at most this number of milliseconds to finish processing of pending signals
-const int MAX_WAIT_MILLIS = 2000;
-
-
-void JStack::signalHandler(int signo, siginfo_t* siginfo, void* ucontext) {
-    ExecutionEvent event;
-    event._thread_state = Profiler::_instance.getThreadState(ucontext);
-    Profiler::_instance.recordSample(ucontext, 1, 0, &event);
-}
-
-Error JStack::start(Arguments& args) {
-    OS::installSignalHandler(SIGVTALRM, signalHandler);
-
-    int self = OS::threadId();
-    u64 required_samples = Profiler::_instance.total_samples();
-    ThreadFilter* thread_filter = Profiler::_instance.threadFilter();
-    bool thread_filter_enabled = thread_filter->enabled();
-
-    ThreadList* thread_list = OS::listThreads();
-    int thread_id;
-    while ((thread_id = thread_list->next()) != -1) {
-        if (thread_id != self && (!thread_filter_enabled || thread_filter->accept(thread_id))) {
-            if (OS::sendSignalToThread(thread_id, SIGVTALRM)) {
-                required_samples++;
-            }
-        }
-    }
-    delete thread_list;
-
-    // Get our own stack trace after all other threads
-    if (!thread_filter_enabled || thread_filter->accept(self)) {
-        ExecutionEvent event;
-        event._thread_state = THREAD_RUNNING;
-        Profiler::_instance.recordSample(NULL, 1, 0, &event);
-        required_samples++;
-    }
-
-    // Wait until all asynchronous stack traces collected
-    for (int i = 0; Profiler::_instance.total_samples() < required_samples && i < MAX_WAIT_MILLIS; i++) {
-        struct timespec timeout = {0, 1000000};
-        nanosleep(&timeout, NULL);
-    }
-
-    return Error::OK;
-}
-
-void JStack::stop() {
-    // Nothing to do
-}

src/linearAllocator.cpp

@@ -41,6 +41,26 @@ void LinearAllocator::clear() {
     _tail->offs = sizeof(Chunk);
 }
 
+size_t LinearAllocator::usedMemory() {
+    size_t bytes = _reserve->prev == _tail ? _chunk_size : 0;
+    for (Chunk* chunk = _tail; chunk != NULL; chunk = chunk->prev) {
+        bytes += _chunk_size;
+    }
+    return bytes;
+}
+
+Chunk* LinearAllocator::trim() {
+    return __atomic_exchange_n(&_tail->prev, NULL, __ATOMIC_ACQ_REL);
+}
+
+void LinearAllocator::freeChain(Chunk* chunk) {
+    while (chunk != NULL) {
+        Chunk* current = chunk;
+        chunk = chunk->prev;
+        freeChunk(current);
+    }
+}
+
 void* LinearAllocator::alloc(size_t size) {
     Chunk* chunk = _tail;
 

src/linearAllocator.h

@@ -43,6 +43,9 @@ class LinearAllocator {
     ~LinearAllocator();
 
     void clear();
+    size_t usedMemory();
+    Chunk* trim();
+    void freeChain(Chunk* chunk);
 
     void* alloc(size_t size);
 };

src/lockTracer.cpp

@@ -16,31 +16,37 @@
 
 #include <string.h>
 #include "lockTracer.h"
-#include "os.h"
 #include "profiler.h"
-#include "vmStructs.h"
+#include "tsc.h"
 
 
+double LockTracer::_ticks_to_nanos;
+jlong LockTracer::_threshold;
 jlong LockTracer::_start_time = 0;
+jclass LockTracer::_UnsafeClass = NULL;
 jclass LockTracer::_LockSupport = NULL;
 jmethodID LockTracer::_getBlocker = NULL;
+RegisterNativesFunc LockTracer::_orig_RegisterNatives = NULL;
+UnsafeParkFunc LockTracer::_orig_Unsafe_park = NULL;
+bool LockTracer::_initialized = false;
 
 Error LockTracer::start(Arguments& args) {
+    _ticks_to_nanos = 1e9 / TSC::frequency();
+    _threshold = (jlong)(args._lock * (TSC::frequency() / 1e9));
+
+    if (!_initialized) {
+        initialize();
+    }
+
     // Enable Java Monitor events
     jvmtiEnv* jvmti = VM::jvmti();
     jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_MONITOR_CONTENDED_ENTER, NULL);
     jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_MONITOR_CONTENDED_ENTERED, NULL);
-    _start_time = OS::nanotime();
+    _start_time = TSC::ticks();
 
-    if (_getBlocker == NULL) {
-        JNIEnv* env = VM::jni();
-        _LockSupport = (jclass)env->NewGlobalRef(env->FindClass("java/util/concurrent/locks/LockSupport"));
-        _getBlocker = env->GetStaticMethodID(_LockSupport, "getBlocker", "(Ljava/lang/Thread;)Ljava/lang/Object;");
-    }
-
-    // Intercent Unsafe.park() for tracing contended ReentrantLocks
-    if (VMStructs::_unsafe_park != NULL) {
-        bindUnsafePark(UnsafeParkTrap);
+    // Intercept Unsafe.park() for tracing contended ReentrantLocks
+    if (_orig_Unsafe_park != NULL) {
+        bindUnsafePark(UnsafeParkHook);
     }
 
     return Error::OK;
@@ -53,48 +59,98 @@ void LockTracer::stop() {
     jvmti->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_MONITOR_CONTENDED_ENTERED, NULL);
 
     // Reset Unsafe.park() trap
-    if (VMStructs::_unsafe_park != NULL) {
-        bindUnsafePark(VMStructs::_unsafe_park);
+    if (_orig_Unsafe_park != NULL) {
+        bindUnsafePark(_orig_Unsafe_park);
     }
 }
 
+void LockTracer::initialize() {
+    jvmtiEnv* jvmti = VM::jvmti();
+    JNIEnv* env = VM::jni();
+
+    // Try JDK 9+ package first, then fallback to JDK 8 package
+    jclass unsafe = env->FindClass("jdk/internal/misc/Unsafe");
+    if (unsafe == NULL) {
+        env->ExceptionClear();
+        if ((unsafe = env->FindClass("sun/misc/Unsafe")) == NULL) {
+            env->ExceptionClear();
+            return;
+        }
+    }
+
+    _UnsafeClass = (jclass)env->NewGlobalRef(unsafe);
+    jmethodID register_natives = env->GetStaticMethodID(_UnsafeClass, "registerNatives", "()V");
+    jniNativeInterface* jni_functions;
+    if (register_natives != NULL && jvmti->GetJNIFunctionTable(&jni_functions) == 0) {
+        _orig_RegisterNatives = jni_functions->RegisterNatives;
+        jni_functions->RegisterNatives = RegisterNativesHook;
+        jvmti->SetJNIFunctionTable(jni_functions);
+
+        // Trace Unsafe.registerNatives() to find the original address of Unsafe.park() native  
+        env->CallStaticVoidMethod(_UnsafeClass, register_natives);
+
+        jni_functions->RegisterNatives = _orig_RegisterNatives;
+        jvmti->SetJNIFunctionTable(jni_functions);
+    }
+
+    _LockSupport = (jclass)env->NewGlobalRef(env->FindClass("java/util/concurrent/locks/LockSupport"));
+    _getBlocker = env->GetStaticMethodID(_LockSupport, "getBlocker", "(Ljava/lang/Thread;)Ljava/lang/Object;");
+
+    env->ExceptionClear();
+    _initialized = true;
+}
+
 void JNICALL LockTracer::MonitorContendedEnter(jvmtiEnv* jvmti, JNIEnv* env, jthread thread, jobject object) {
-    jlong enter_time = OS::nanotime();
+    jlong enter_time = TSC::ticks();
     jvmti->SetTag(thread, enter_time);
 }
 
 void JNICALL LockTracer::MonitorContendedEntered(jvmtiEnv* jvmti, JNIEnv* env, jthread thread, jobject object) {
-    jlong entered_time = OS::nanotime();
+    jlong entered_time = TSC::ticks();
     jlong enter_time;
     jvmti->GetTag(thread, &enter_time);
 
     // Time is meaningless if lock attempt has started before profiling
-    if (_enabled && enter_time >= _start_time) {
+    if (_enabled && entered_time - enter_time >= _threshold && enter_time >= _start_time) {
         char* lock_name = getLockName(jvmti, env, object);
         recordContendedLock(BCI_LOCK, enter_time, entered_time, lock_name, object, 0);
         jvmti->Deallocate((unsigned char*)lock_name);
     }
 }
 
-void JNICALL LockTracer::UnsafeParkTrap(JNIEnv* env, jobject instance, jboolean isAbsolute, jlong time) {
+jint JNICALL LockTracer::RegisterNativesHook(JNIEnv* env, jclass cls, const JNINativeMethod* methods, jint nMethods) {
+    if (env->IsSameObject(cls, _UnsafeClass)) {
+        for (jint i = 0; i < nMethods; i++) {
+            if (strcmp(methods[i].name, "park") == 0 && strcmp(methods[i].signature, "(ZJ)V") == 0) {
+                _orig_Unsafe_park = (UnsafeParkFunc)methods[i].fnPtr;
+                break;
+            } 
+        }
+        return 0;
+    }
+    return _orig_RegisterNatives(env, cls, methods, nMethods);
+}
+
+void JNICALL LockTracer::UnsafeParkHook(JNIEnv* env, jobject instance, jboolean isAbsolute, jlong time) {
     jvmtiEnv* jvmti = VM::jvmti();
     jobject park_blocker = _enabled ? getParkBlocker(jvmti, env) : NULL;
     jlong park_start_time, park_end_time;
 
     if (park_blocker != NULL) {
-        park_start_time = OS::nanotime();
+        park_start_time = TSC::ticks();
     }
 
-    VMStructs::_unsafe_park(env, instance, isAbsolute, time);
+    _orig_Unsafe_park(env, instance, isAbsolute, time);
 
     if (park_blocker != NULL) {
-        park_end_time = OS::nanotime();
-
-        char* lock_name = getLockName(jvmti, env, park_blocker);
-        if (lock_name == NULL || isConcurrentLock(lock_name)) {
-            recordContendedLock(BCI_PARK, park_start_time, park_end_time, lock_name, park_blocker, time);
+        park_end_time = TSC::ticks();
+        if (park_end_time - park_start_time >= _threshold) {
+            char* lock_name = getLockName(jvmti, env, park_blocker);
+            if (lock_name == NULL || isConcurrentLock(lock_name)) {
+                recordContendedLock(BCI_PARK, park_start_time, park_end_time, lock_name, park_blocker, time);
+            }
+            jvmti->Deallocate((unsigned char*)lock_name);
         }
-        jvmti->Deallocate((unsigned char*)lock_name);
     }
 }
 
@@ -134,26 +190,20 @@ void LockTracer::recordContendedLock(int event_type, u64 start_time, u64 end_tim
 
     if (lock_name != NULL) {
         if (lock_name[0] == 'L') {
-            event._class_id = Profiler::_instance.classMap()->lookup(lock_name + 1, strlen(lock_name) - 2);
+            event._class_id = Profiler::instance()->classMap()->lookup(lock_name + 1, strlen(lock_name) - 2);
         } else {
-            event._class_id = Profiler::_instance.classMap()->lookup(lock_name);
+            event._class_id = Profiler::instance()->classMap()->lookup(lock_name);
         }
     }
 
-    Profiler::_instance.recordSample(NULL, end_time - start_time, event_type, &event);
+    u64 duration_nanos = (u64)((end_time - start_time) * _ticks_to_nanos);
+    Profiler::instance()->recordSample(NULL, duration_nanos, event_type, &event);
 }
 
 void LockTracer::bindUnsafePark(UnsafeParkFunc entry) {
     JNIEnv* env = VM::jni();
-
-    // Try JDK 9+ package first, then fallback to JDK 8 package
-    jclass unsafe = env->FindClass("jdk/internal/misc/Unsafe");
-    if (unsafe == NULL) unsafe = env->FindClass("sun/misc/Unsafe");
-
-    if (unsafe != NULL) {
-        const JNINativeMethod unsafe_park = {(char*)"park", (char*)"(ZJ)V", (void*)entry};
-        env->RegisterNatives(unsafe, &unsafe_park, 1);
+    const JNINativeMethod park = {(char*)"park", (char*)"(ZJ)V", (void*)entry};
+    if (env->RegisterNatives(_UnsafeClass, &park, 1) != 0) {
+        env->ExceptionClear();
     }
-
-    env->ExceptionClear();
 }

src/lockTracer.h

@@ -22,13 +22,26 @@
 #include "engine.h"
 
 
+typedef jint (JNICALL *RegisterNativesFunc)(JNIEnv*, jclass, const JNINativeMethod*, jint);
 typedef void (JNICALL *UnsafeParkFunc)(JNIEnv*, jobject, jboolean, jlong);
 
 class LockTracer : public Engine {
   private:
+    static double _ticks_to_nanos;
+    static jlong _threshold;
     static jlong _start_time;
+    static jclass _UnsafeClass;
     static jclass _LockSupport;
     static jmethodID _getBlocker;
+    static bool _initialized;
+
+    static void initialize();
+
+    static RegisterNativesFunc _orig_RegisterNatives;
+    static jint JNICALL RegisterNativesHook(JNIEnv* env, jclass cls, const JNINativeMethod* methods, jint nMethods);
+
+    static UnsafeParkFunc _orig_Unsafe_park;
+    static void JNICALL UnsafeParkHook(JNIEnv* env, jobject instance, jboolean isAbsolute, jlong time);
 
     static jobject getParkBlocker(jvmtiEnv* jvmti, JNIEnv* env);
     static char* getLockName(jvmtiEnv* jvmti, JNIEnv* env, jobject lock);
@@ -38,24 +51,19 @@ class LockTracer : public Engine {
     static void bindUnsafePark(UnsafeParkFunc entry);
 
   public:
-    const char* name() {
-        return "lock";
+    const char* title() {
+        return "Lock profile";
     }
 
     const char* units() {
         return "ns";
     }
 
-    CStack cstack() {
-        return CSTACK_NO;
-    }
-
     Error start(Arguments& args);
     void stop();
 
     static void JNICALL MonitorContendedEnter(jvmtiEnv* jvmti, JNIEnv* env, jthread thread, jobject object);
     static void JNICALL MonitorContendedEntered(jvmtiEnv* jvmti, JNIEnv* env, jthread thread, jobject object);
-    static void JNICALL UnsafeParkTrap(JNIEnv* env, jobject instance, jboolean isAbsolute, jlong time);
 };
 
 #endif // _LOCKTRACER_H

src/log.cpp

@@ -0,0 +1,127 @@
+/*
+ * Copyright 2021 Andrei Pangin
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <string.h>
+#include "log.h"
+#include "profiler.h"
+
+
+const char* const Log::LEVEL_NAME[] = {
+    "TRACE",
+    "DEBUG",
+    "INFO",
+    "WARN",
+    "ERROR",
+    "NONE"
+};
+
+FILE* Log::_file = stdout;
+LogLevel Log::_level = LOG_TRACE;
+
+
+void Log::open(Arguments& args) {
+    open(args._log, args._loglevel);
+
+    if (args._unknown_arg != NULL) {
+       warn("Unknown argument: %s", args._unknown_arg);
+    }
+}
+
+void Log::open(const char* file_name, const char* level) {
+    if (_file != stdout && _file != stderr) {
+        fclose(_file);
+    }
+
+    if (file_name == NULL || strcmp(file_name, "stdout") == 0) {
+        _file = stdout;
+    } else if (strcmp(file_name, "stderr") == 0) {
+        _file = stderr;
+    } else if ((_file = fopen(file_name, "w")) == NULL) {
+        _file = stdout;
+        warn("Could not open log file: %s", file_name);
+    }
+
+    LogLevel l = LOG_TRACE;
+    if (level != NULL) {
+        for (int i = LOG_TRACE; i <= LOG_NONE; i++) {
+            if (strcasecmp(LEVEL_NAME[i], level) == 0) {
+                l = (LogLevel)i;
+                break;
+            }
+        }
+    }
+    __atomic_store_n(&_level, l, __ATOMIC_RELEASE);
+}
+
+void Log::close() {
+    if (_file != stdout && _file != stderr) {
+        fclose(_file);
+        _file = stdout;
+    }
+}
+
+void Log::log(LogLevel level, const char* msg, va_list args) {
+    char buf[1024];
+    size_t len = vsnprintf(buf, sizeof(buf), msg, args);
+    if (len >= sizeof(buf)) {
+        len = sizeof(buf) - 1;
+        buf[len] = 0;
+    }
+
+    if (level < LOG_ERROR) {
+        Profiler::instance()->writeLog(level, buf, len);
+    }
+
+    if (level >= _level) {
+        fprintf(_file, "[%s] %s\n", LEVEL_NAME[level], buf);
+        fflush(_file);
+    }
+}
+
+void Log::trace(const char* msg, ...) {
+    va_list args;
+    va_start(args, msg);
+    log(LOG_TRACE, msg, args);
+    va_end(args);
+}
+
+void Log::debug(const char* msg, ...) {
+    va_list args;
+    va_start(args, msg);
+    log(LOG_DEBUG, msg, args);
+    va_end(args);
+}
+
+void Log::info(const char* msg, ...) {
+    va_list args;
+    va_start(args, msg);
+    log(LOG_INFO, msg, args);
+    va_end(args);
+}
+
+void Log::warn(const char* msg, ...) {
+    va_list args;
+    va_start(args, msg);
+    log(LOG_WARN, msg, args);
+    va_end(args);
+}
+
+void Log::error(const char* msg, ...) {
+    va_list args;
+    va_start(args, msg);
+    log(LOG_ERROR, msg, args);
+    va_end(args);
+}

src/log.h

@@ -0,0 +1,63 @@
+/*
+ * Copyright 2021 Andrei Pangin
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef _LOG_H
+#define _LOG_H
+
+#include <stdarg.h>
+#include <stdio.h>
+
+#ifdef __GNUC__
+#define ATTR_FORMAT __attribute__((format(printf, 1, 2)))
+#else
+#define ATTR_FORMAT
+#endif
+
+
+enum LogLevel {
+    LOG_TRACE,
+    LOG_DEBUG,
+    LOG_INFO,
+    LOG_WARN,
+    LOG_ERROR,
+    LOG_NONE
+};
+
+
+class Arguments;
+
+class Log {
+  private:
+    static FILE* _file;
+    static LogLevel _level;
+
+  public:
+    static const char* const LEVEL_NAME[];
+
+    static void open(Arguments& args);
+    static void open(const char* file_name, const char* level);
+    static void close();
+
+    static void log(LogLevel level, const char* msg, va_list args);
+
+    static void ATTR_FORMAT trace(const char* msg, ...);
+    static void ATTR_FORMAT debug(const char* msg, ...);
+    static void ATTR_FORMAT info(const char* msg, ...);
+    static void ATTR_FORMAT warn(const char* msg, ...);
+    static void ATTR_FORMAT error(const char* msg, ...);
+};
+
+#endif // _LOG_H

src/mutex.cpp

@@ -31,3 +31,16 @@ void Mutex::lock() {
 void Mutex::unlock() {
     pthread_mutex_unlock(&_mutex);
 }
+
+WaitableMutex::WaitableMutex() : Mutex() {
+    pthread_cond_init(&_cond, NULL);
+}
+
+bool WaitableMutex::waitUntil(u64 wall_time) {
+    struct timespec ts = {(time_t)(wall_time / 1000000), (long)(wall_time % 1000000) * 1000};
+    return pthread_cond_timedwait(&_cond, &_mutex, &ts) != 0;
+}
+
+void WaitableMutex::notify() {
+    pthread_cond_signal(&_cond);
+}

src/mutex.h

@@ -18,10 +18,11 @@
 #define _MUTEX_H
 
 #include <pthread.h>
+#include "arch.h"
 
 
 class Mutex {
-  private:
+  protected:
     pthread_mutex_t _mutex;
 
   public:
@@ -31,6 +32,16 @@ class Mutex {
     void unlock();
 };
 
+class WaitableMutex : public Mutex {
+  protected:
+    pthread_cond_t _cond;
+
+  public:
+    WaitableMutex();
+
+    bool waitUntil(u64 wall_time);
+    void notify();
+};
 
 class MutexLocker {
   private:

src/objectSampler.cpp

@@ -0,0 +1,211 @@
+/*
+ * Copyright 2022 Andrei Pangin
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <string.h>
+#include "objectSampler.h"
+#include "profiler.h"
+#include "tsc.h"
+
+
+u64 ObjectSampler::_interval;
+bool ObjectSampler::_live;
+volatile u64 ObjectSampler::_allocated_bytes;
+
+
+static u32 lookupClassId(jvmtiEnv* jvmti, jclass cls) {
+    u32 class_id = 0;
+    char* class_name;
+    if (jvmti->GetClassSignature(cls, &class_name, NULL) == 0) {
+        if (class_name[0] == 'L') {
+            class_id = Profiler::instance()->classMap()->lookup(class_name + 1, strlen(class_name) - 2);
+        } else {
+            class_id = Profiler::instance()->classMap()->lookup(class_name);
+        }
+        jvmti->Deallocate((unsigned char*)class_name);
+    }
+    return class_id;
+}
+
+
+class LiveRefs {
+  private:
+    enum { MAX_REFS = 1024 };
+
+    SpinLock _lock;
+    jweak _refs[MAX_REFS];
+    struct {
+        jlong size;
+        u64 trace;
+        u64 time;
+    } _values[MAX_REFS];
+    bool _full;
+
+    static inline bool collected(jweak w) {
+        return *(void**)((uintptr_t)w & ~(uintptr_t)1) == NULL;
+    }
+
+  public:
+    LiveRefs() : _lock(1) {
+    }
+
+    void init() {
+        memset(_refs, 0, sizeof(_refs));
+        memset(_values, 0, sizeof(_values));
+        _full = false;
+        _lock.unlock();
+    }
+
+    void gc() {
+        _full = false;
+    }
+
+    void add(JNIEnv* jni, jobject object, jlong size, u64 trace) {
+        if (_full) {
+            return;
+        }
+
+        jweak wobject = jni->NewWeakGlobalRef(object);
+        if (wobject == NULL) {
+            return;
+        }
+
+        if (_lock.tryLock()) {
+            u32 start = (((uintptr_t)object >> 4) * 31 + ((uintptr_t)jni >> 4) + trace) & (MAX_REFS - 1);
+            u32 i = start;
+            do {
+                jweak w = _refs[i];
+                if (w == NULL || collected(w)) {
+                    if (w != NULL) jni->DeleteWeakGlobalRef(w);
+                    _refs[i] = wobject;
+                    _values[i].size = size;
+                    _values[i].trace = trace;
+                    _values[i].time = TSC::ticks();
+                    _lock.unlock();
+                    return;
+                }
+            } while ((i = (i + 1) & (MAX_REFS - 1)) != start);
+
+            _full = true;
+            _lock.unlock();
+        }
+
+        jni->DeleteWeakGlobalRef(wobject);
+    }
+
+    void dump(JNIEnv* jni) {
+        _lock.lock();
+
+        jvmtiEnv* jvmti = VM::jvmti();
+        Profiler* profiler = Profiler::instance();
+
+        for (u32 i = 0; i < MAX_REFS; i++) {
+            if ((i % 32) == 0) jni->PushLocalFrame(64);
+
+            jweak w = _refs[i];
+            if (w != NULL) {
+                jobject obj = jni->NewLocalRef(w);
+                if (obj != NULL) {
+                    LiveObject event;
+                    event._alloc_size = _values[i].size;
+                    event._alloc_time = _values[i].time;
+                    event._class_id = lookupClassId(jvmti, jni->GetObjectClass(obj));
+
+                    int tid = _values[i].trace >> 32;
+                    u32 call_trace_id = (u32)_values[i].trace;
+                    profiler->recordExternalSample(event._alloc_size, tid, BCI_LIVE_OBJECT, &event, call_trace_id);
+                }
+                jni->DeleteWeakGlobalRef(w);
+            }
+
+            if ((i % 32) == 31 || i == MAX_REFS - 1) jni->PopLocalFrame(NULL);
+        }
+    }
+};
+
+static LiveRefs live_refs;
+
+
+void ObjectSampler::SampledObjectAlloc(jvmtiEnv* jvmti, JNIEnv* jni, jthread thread,
+                                       jobject object, jclass object_klass, jlong size) {
+    if (_enabled) {
+        recordAllocation(jvmti, jni, BCI_ALLOC, object, object_klass, size);
+    }
+}
+
+void ObjectSampler::GarbageCollectionStart(jvmtiEnv* jvmti) {
+    live_refs.gc();
+}
+
+void ObjectSampler::recordAllocation(jvmtiEnv* jvmti, JNIEnv* jni, int event_type,
+                                     jobject object, jclass object_klass, jlong size) {
+    AllocEvent event;
+    event._total_size = size > _interval ? size : _interval;
+    event._instance_size = size;
+    event._class_id = lookupClassId(jvmti, object_klass);
+
+    if (_live) {
+        u64 trace = Profiler::instance()->recordSample(NULL, 0, event_type, &event);
+        live_refs.add(jni, object, size, trace);
+    } else {
+        Profiler::instance()->recordSample(NULL, size, event_type, &event);
+    }
+}
+
+void ObjectSampler::initLiveRefs(bool live) {
+    _live = live;
+    if (_live) {
+        live_refs.init();
+    }
+}
+
+void ObjectSampler::dumpLiveRefs() {
+    if (_live) {
+        live_refs.dump(VM::jni());
+    }
+}
+
+Error ObjectSampler::check(Arguments& args) {
+    if (!VM::canSampleObjects()) {
+        return Error("SampledObjectAlloc is not supported on this JVM");
+    }
+    return Error::OK;
+}
+
+Error ObjectSampler::start(Arguments& args) {
+    Error error = check(args);
+    if (error) {
+        return error;
+    }
+
+    _interval = args._alloc > 0 ? args._alloc : DEFAULT_ALLOC_INTERVAL;
+
+    initLiveRefs(args._live);
+
+    jvmtiEnv* jvmti = VM::jvmti();
+    jvmti->SetHeapSamplingInterval(_interval);
+    jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_SAMPLED_OBJECT_ALLOC, NULL);
+    jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_GARBAGE_COLLECTION_START, NULL);
+
+    return Error::OK;
+}
+
+void ObjectSampler::stop() {
+    jvmtiEnv* jvmti = VM::jvmti();
+    jvmti->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_GARBAGE_COLLECTION_START, NULL);
+    jvmti->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_SAMPLED_OBJECT_ALLOC, NULL);
+
+    dumpLiveRefs();
+}