Can Linux perf compare per - thread performance?

Question

I know perf can profile single progress or single thread use perf stat -p tid/pid or perf top -p tid/pid.

But I want to profile per-thread in a progress, and compare event, get which thread is high consumption, then to optimize it. Can perf do this ? if not, which tools can do that ?

thanks.

Is your problem Python specific ? – Pe Dro Jun 17 '20 at 06:03 — Pe Dro, Jun 17 '20 at 06:03

score 3 · Answer 1 · answered Apr 11 '16 at 13:58

There was proposed patch to add --per-thread option to perf stat (and with interval mode -I 1000 it is possible to see current counters every second for every thread ): https://lwn.net/Articles/649001/ "perf stat: Introduce --per-thread option" From: Jiri Olsa, Date: Tue, 23 Jun 2015

adding the possibility to display stat data per thread.

Allowing following commands and output:

$ perf stat -e cycles,instructions --per-thread -p 30190,30242 ^C Performance counter stats for process id '30190,30242':

           cat-30190                     0      cycles
           yes-30242         3,842,525,421      cycles
           cat-30190                     0      instructions
           yes-30242        10,370,817,010      instructions

     1.143155657 seconds time elapsed

Also works under interval mode:

$ perf stat -e cycles,instructions --per-thread -p 30190,30242 -I 1000

#           time             comm-pid                  counts   unit events
   1.000073435              cat-30190                89,058      cycles
   1.000073435              yes-30242         3,360,786,902      cycles                     (100.00%)
   1.000073435              cat-30190                14,066      instructions
   1.000073435              yes-30242         9,069,937,462      instructions
   2.000204830              cat-30190                     0      cycles
   2.000204830              yes-30242         3,351,667,626      cycles
   2.000204830              cat-30190                     0      instructions
   2.000204830              yes-30242         9,045,796,885      instructions   
  ^C
   2.771286639              cat-30190                     0      cycles
   2.771286639              yes-30242         2,593,884,166      cycles
   2.771286639              cat-30190                     0      instructions
   2.771286639              yes-30242         7,001,171,191      instructions

Available in here:
git://git.kernel.org/pub/scm/linux/kernel/git/jolsa/perf.git
perf/per_thread

What if the pid/ tid is not known? In a scenario where the application is invoked like `perf stat -e ./myApp` — talekeDskobeDa, Feb 13 '19 at 17:33

score 1 · Answer 2 · edited Dec 21 '15 at 07:20

1

Yes. Of course.

You could use perf_event_open() system call to open performance counters. and then use proctl/ioctl to read counters.

You could check linux man pages for all the details.

edited Dec 21 '15 at 07:20

Serjik

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answered Dec 21 '15 at 04:54

L.Y.

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score -2 · Answer 3 · edited May 23 '17 at 11:54

-2

Do you see this question?

How to profile multi-threaded C++ application on Linux?

I think you could start with valgrind:

http://valgrind.org/docs/manual/cl-manual.html

edited May 23 '17 at 11:54

Community

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answered Jul 09 '14 at 09:28

Klaus

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Can Linux perf compare per - thread performance?

3 Answers3