Andi Kleen
dde4e732a5
When we hit the end of a program block, need to count the last
instruction too for the IPC computation. This caused large errors for
small blocks.
% perf script -b ls / > /dev/null
Before:
% perf script -F +brstackinsn --xed
...
00007f94c9ac70d8 jz 0x7f94c9ac70e3 # PRED 3 cycles [36] 4.33 IPC
00007f94c9ac70e3 testb $0x20, 0x31d(%rbx)
00007f94c9ac70ea jnz 0x7f94c9ac70b0
00007f94c9ac70ec testb $0x8, 0x205ad(%rip)
00007f94c9ac70f3 jz 0x7f94c9ac6ff0 # PRED 1 cycles [37] 3.00 IPC
After:
% perf script -F +brstackinsn --xed
...
00007f94c9ac70d8 jz 0x7f94c9ac70e3 # PRED 3 cycles [15] 4.67 IPC
00007f94c9ac70e3 testb $0x20, 0x31d(%rbx)
00007f94c9ac70ea jnz 0x7f94c9ac70b0
00007f94c9ac70ec testb $0x8, 0x205ad(%rip)
00007f94c9ac70f3 jz 0x7f94c9ac6ff0 # PRED 1 cycles [16] 4.00 IPC
Suggested-by: Denis Bakhvalov <denis.bakhvalov@intel.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Link: http://lkml.kernel.org/r/20190711181922.18765-2-andi@firstfloor.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.