Can not trace perf-probe event (made to probe the main function) with perf-top

Can not trace perf-probe event (made to probe the main function) with perf-top

[HOUSSEN Franck]

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Can not trace perf-probe event (made to probe the main function) with
perf-top ? (see ReadMe.txt - works with perf-report and -s option)
Can someone help ? Missing option ? Known bug / limitation ?

Thanks,

Franck

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/tmp> more main.cpp
#include <unistd.h> // sleep
int main(void) { sleep(10); return 0; }

/tmp> gcc -g main.cpp -o main

/tmp> sudo perf probe --exec ./main --add main
Added new event:
  probe_main:main      (on main in /tmp/main)
  You can now use it in all perf tools, such as:
    perf record -e probe_main:main -aR sleep 1

/tmp> sudo perf record -e probe_main:main ./main
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.017 MB perf.data (1 samples) ]

/tmp> sudo perf report --stdio -s sym,dso
# To display the perf.data header info, please use --header/--header-only options.
#
#
# Total Lost Samples: 0
#
# Samples: 1  of event 'probe_main:main'
# Event count (approx.): 1
#
# Overhead  Trace output
# ........  ............
#
   100.00%  main
#
# (Tip: List events using substring match: perf list <keyword>)
#

~> sudo perf top -K --stdio -s sym,dso -e probe_main:main
   PerfTop:       0 irqs/sec  kernel: 0.0%  exact:  0.0% [1Hz probe_main:main],  (all, 4 CPUs)
   -------------------------------------------------------------------------------------------

~> lsb_release -a
No LSB modules are available.
Distributor ID: Debian
Description:  Debian GNU/Linux testing (stretch)
Release:  testing
Codename: stretch

~> cat /proc/sys/kernel/perf_event_paranoid
-1

~> cat /proc/sys/kernel/kptr_restrict
0

~> gcc --version
gcc (Debian 6.2.0-10) 6.2.0 20161027

~> perf --version
perf version 4.7.8

~> uname -a
Linux yoda 4.7.0-1-amd64 #1 SMP Debian 4.7.8-1 (2016-10-19) x86_64 GNU/Linux

Re: Can not trace perf-probe event (made to probe the main function) with perf-top

[Masami Hiramatsu]

Hello Franck,

On Sat, 19 Nov 2016 17:36:39 +0100
HOUSSEN Franck <fghoussen@gmail.com> wrote:

> Can not trace perf-probe event (made to probe the main function) with
> perf-top ? (see ReadMe.txt - works with perf-report and -s option)
> Can someone help ? Missing option ? Known bug / limitation ?

From ReadMe.txt;
----
~> sudo perf top -K --stdio -s sym,dso -e probe_main:main
   PerfTop:       0 irqs/sec  kernel: 0.0%  exact:  0.0% [1Hz probe_main:main],  (all, 4 CPUs)
   -------------------------------------------------------------------------------------------
----
Have you tried to run ./main program while running "perf top"?

Since the main function is just called once when starting run
the main program, without invoking it, the probe_main:main
may never be occured.

Thanks,
-- 
Masami Hiramatsu <mhiramat@kernel.org>

Re: Can not trace perf-probe event (made to probe the main function) with perf-top

[HOUSSEN Franck]

Oh dear !... You are right ! Thanks,

Franck

2016-11-20 14:26 GMT+01:00 Masami Hiramatsu <mhiramat@kernel.org>:
> Hello Franck,
>
> On Sat, 19 Nov 2016 17:36:39 +0100
> HOUSSEN Franck <fghoussen@gmail.com> wrote:
>
>> Can not trace perf-probe event (made to probe the main function) with
>> perf-top ? (see ReadMe.txt - works with perf-report and -s option)
>> Can someone help ? Missing option ? Known bug / limitation ?
>
> From ReadMe.txt;
> ----
> ~> sudo perf top -K --stdio -s sym,dso -e probe_main:main
>    PerfTop:       0 irqs/sec  kernel: 0.0%  exact:  0.0% [1Hz probe_main:main],  (all, 4 CPUs)
>    -------------------------------------------------------------------------------------------
> ----
> Have you tried to run ./main program while running "perf top"?
>
> Since the main function is just called once when starting run
> the main program, without invoking it, the probe_main:main
> may never be occured.
>
> Thanks,
> --
> Masami Hiramatsu <mhiramat@kernel.org>



-- 
Bonne journée,

Franck HOUSSEN