Messages in this thread | | | From | Namhyung Kim <> | Date | Thu, 6 Oct 2022 16:13:59 -0700 | Subject | Re: [PATCH 1/5] libperf: Populate system-wide evsel maps |
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Hi Ian,
On Thu, Oct 6, 2022 at 11:44 AM Ian Rogers <irogers@google.com> wrote: > > On Mon, Oct 3, 2022 at 1:46 PM Namhyung Kim <namhyung@kernel.org> wrote: > > > > Setting proper cpu and thread maps for system wide evsels regardless of > > user requested cpu in __perf_evlist__propagate_maps(). Those evsels > > need to be active on all cpus always. Do it in the libperf so that we > > can guarantee it has proper maps. > > > > Reviewed-by: Adrian Hunter <adrian.hunter@intel.com> > > Signed-off-by: Namhyung Kim <namhyung@kernel.org> > > --- > > tools/lib/perf/evlist.c | 15 +++++++++------ > > 1 file changed, 9 insertions(+), 6 deletions(-) > > > > diff --git a/tools/lib/perf/evlist.c b/tools/lib/perf/evlist.c > > index 6b1bafe267a4..187129652ab6 100644 > > --- a/tools/lib/perf/evlist.c > > +++ b/tools/lib/perf/evlist.c > > @@ -40,11 +40,11 @@ static void __perf_evlist__propagate_maps(struct perf_evlist *evlist, > > * We already have cpus for evsel (via PMU sysfs) so > > * keep it, if there's no target cpu list defined. > > */ > > This comment is for the 'else if' case and so is a little out of place > before the system wide test.
Right, I'll add a comment for system-wide evsels too.
> > > - if (!evsel->own_cpus || > > - (!evsel->system_wide && evlist->has_user_cpus) || > > - (!evsel->system_wide && > > - !evsel->requires_cpu && > > - perf_cpu_map__empty(evlist->user_requested_cpus))) { > > + if (evsel->system_wide) { > > + perf_cpu_map__put(evsel->cpus); > > + evsel->cpus = perf_cpu_map__new(NULL); > > Looking at perf_cpu_map__new, will this mean that in system wide mode > every event/evsel will now read /sys/devices/system/cpu/online here? > We may want to cache the cpumap to avoid this.
Yeah, it's redundant. I thought it's ok since the system-wide evsels are not common. We can consider caching when it becomes a problem.
Thanks, Namhyung
> > > + } else if (!evsel->own_cpus || evlist->has_user_cpus || > > + (!evsel->requires_cpu && perf_cpu_map__empty(evlist->user_requested_cpus))) { > > perf_cpu_map__put(evsel->cpus); > > evsel->cpus = perf_cpu_map__get(evlist->user_requested_cpus); > > } else if (evsel->cpus != evsel->own_cpus) { > > @@ -52,7 +52,10 @@ static void __perf_evlist__propagate_maps(struct perf_evlist *evlist, > > evsel->cpus = perf_cpu_map__get(evsel->own_cpus); > > } > > > > - if (!evsel->system_wide) { > > + if (evsel->system_wide) { > > + perf_thread_map__put(evsel->threads); > > + evsel->threads = perf_thread_map__new_dummy(); > > + } else { > > perf_thread_map__put(evsel->threads); > > evsel->threads = perf_thread_map__get(evlist->threads); > > } > > -- > > 2.38.0.rc1.362.ged0d419d3c-goog > >
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