Messages in this thread | | | From | Namhyung Kim <> | Date | Tue, 17 Oct 2023 12:05:40 -0700 | Subject | Re: [perf stat] Extend --cpu to non-system-wide runs too? was Re: [PATCH v3] perf bench sched pipe: Add -G/--cgroups option |
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On Tue, Oct 17, 2023 at 11:31 AM Arnaldo Carvalho de Melo <acme@kernel.org> wrote: > > Em Tue, Oct 17, 2023 at 02:43:45PM +0200, Ingo Molnar escreveu: > > * Arnaldo Carvalho de Melo <acme@kernel.org> wrote: > > > Em Tue, Oct 17, 2023 at 01:40:07PM +0200, Ingo Molnar escreveu: > > > > Side note: it might make sense to add a sane cpumask/affinity setting > > > > option to perf stat itself: > > > > > perf stat --cpumask > > > > > ... or so? > > > > > We do have -C: > > > > > -C, --cpu <cpu> list of cpus to monitor in system-wide > > > > > ... but that's limited to --all-cpus, right? > > > > > Perhaps we could extend --cpu to non-system-wide runs too? > > > > Maybe I misunderstood your question, but its a list of cpus to limit the > > > counting: > > > Ok. > > > So I thought that "--cpumask mask/list/etc" should simply do what 'taskset' > > is doing: using the sched_setaffinity() syscall to make the current > > workload and all its children. > > > There's impact on perf stat itself: it could just call sched_setaffinity() > > early on, and not bother about it? > > > Having it built-in into perf would simply make it easier to not forget > > running 'taskset'. :-) > > Would that be the only advantage? > > I think using taskset isn't that much of a burden and keeps with the > Unix tradition, no? :-\
Agreed. Maybe there's a usecase that wants to profile a specific cpu while the target processes are running all available cpus.
Thanks, Namhyung
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