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* libperf : Can not create event group
@ 2021-06-14  7:17 nakamura.shun
  2021-06-14 11:17 ` Jiri Olsa
  0 siblings, 1 reply; 5+ messages in thread
From: nakamura.shun @ 2021-06-14  7:17 UTC (permalink / raw)
  To: peterz, mingo, acme, mark.rutland, alexander.shishkin, jolsa, namhyung
  Cc: linux-perf-users, linux-kernel

Hello.

perf_evsel__open cannot create an event group because it set group_fd
to -1 when it ran perf_event_open.
Is there any reason why group_fd is fixed at -1?

Best Regards
Shunsuke

^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: libperf : Can not create event group
  2021-06-14  7:17 libperf : Can not create event group nakamura.shun
@ 2021-06-14 11:17 ` Jiri Olsa
  2021-06-22  7:57   ` nakamura.shun
  0 siblings, 1 reply; 5+ messages in thread
From: Jiri Olsa @ 2021-06-14 11:17 UTC (permalink / raw)
  To: nakamura.shun
  Cc: peterz, mingo, acme, mark.rutland, alexander.shishkin, namhyung,
	linux-perf-users, linux-kernel

On Mon, Jun 14, 2021 at 07:17:53AM +0000, nakamura.shun@fujitsu.com wrote:
> Hello.
> 
> perf_evsel__open cannot create an event group because it set group_fd
> to -1 when it ran perf_event_open.
> Is there any reason why group_fd is fixed at -1?

hi,
there'no leader link on this level yet (in struct evsel)
so this is not implemented at the moment

jirka

> 
> Best Regards
> Shunsuke


^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: libperf : Can not create event group
  2021-06-14 11:17 ` Jiri Olsa
@ 2021-06-22  7:57   ` nakamura.shun
  2021-06-22 21:06     ` Jiri Olsa
  0 siblings, 1 reply; 5+ messages in thread
From: nakamura.shun @ 2021-06-22  7:57 UTC (permalink / raw)
  To: Jiri Olsa
  Cc: peterz, mingo, acme, mark.rutland, alexander.shishkin, namhyung,
	linux-perf-users, linux-kernel

Hi, jirka

> there'no leader link on this level yet (in struct evsel)
> so this is not implemented at the moment

Thanks for the info.

Do you have any plans to support the event group in libperf?

Best Regards
Shunsuke

^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: libperf : Can not create event group
  2021-06-22  7:57   ` nakamura.shun
@ 2021-06-22 21:06     ` Jiri Olsa
  2021-06-28  8:44       ` nakamura.shun
  0 siblings, 1 reply; 5+ messages in thread
From: Jiri Olsa @ 2021-06-22 21:06 UTC (permalink / raw)
  To: nakamura.shun
  Cc: peterz, mingo, acme, mark.rutland, alexander.shishkin, namhyung,
	linux-perf-users, linux-kernel

On Tue, Jun 22, 2021 at 07:57:56AM +0000, nakamura.shun@fujitsu.com wrote:
> Hi, jirka
> 
> > there'no leader link on this level yet (in struct evsel)
> > so this is not implemented at the moment
> 
> Thanks for the info.
> 
> Do you have any plans to support the event group in libperf?

hi,
not until now I guess ;-) what's your use case?

jirka


^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: libperf : Can not create event group
  2021-06-22 21:06     ` Jiri Olsa
@ 2021-06-28  8:44       ` nakamura.shun
  0 siblings, 0 replies; 5+ messages in thread
From: nakamura.shun @ 2021-06-28  8:44 UTC (permalink / raw)
  To: Jiri Olsa
  Cc: peterz, mingo, acme, mark.rutland, alexander.shishkin, namhyung,
	linux-perf-users, linux-kernel

Hi, jirka

> > Do you have any plans to support the event group in libperf?
> 
> hi,
> not until now I guess ;-) what's your use case?

PAPI uses event group to measure multiple events.
libperf uses multiplexing regardless of the user's intent.

I thought it would be nice if users could choose to use multiplexing or event groups.


Best Regards
Shunsuke

jirka

^ permalink raw reply	[flat|nested] 5+ messages in thread

end of thread, other threads:[~2021-06-28  8:52 UTC | newest]

Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
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2021-06-14  7:17 libperf : Can not create event group nakamura.shun
2021-06-14 11:17 ` Jiri Olsa
2021-06-22  7:57   ` nakamura.shun
2021-06-22 21:06     ` Jiri Olsa
2021-06-28  8:44       ` nakamura.shun

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