Messages in this thread | | | From | Ian Rogers <> | Date | Fri, 6 May 2022 13:51:44 -0700 | Subject | Re: [PATCH V2 21/23] libperf evsel: Add comments for booleans |
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On Fri, May 6, 2022 at 5:26 AM Adrian Hunter <adrian.hunter@intel.com> wrote: > > Add comments for 'system_wide' and 'requires_cpu' booleans > > Signed-off-by: Adrian Hunter <adrian.hunter@intel.com> > --- > tools/lib/perf/include/internal/evsel.h | 9 +++++++++ > 1 file changed, 9 insertions(+) > > diff --git a/tools/lib/perf/include/internal/evsel.h b/tools/lib/perf/include/internal/evsel.h > index 77fbb8b97e5c..cc8f1ba790bd 100644 > --- a/tools/lib/perf/include/internal/evsel.h > +++ b/tools/lib/perf/include/internal/evsel.h > @@ -49,7 +49,16 @@ struct perf_evsel { > > /* parse modifier helper */ > int nr_members; > + /* > + * system_wide is for events that need to be on every CPU, irrespective > + * of user requested CPUs or threads. Map propagation will not override > + * this events own_cpus, which will contribute to evlist all_cpus.
So this muddies my understanding of cpus and own_cpus (sigh, again undocumented). I believe cpus to be the set of CPUs (or any CPU, aka dummy) that perf_event_open happens on. all_cpus in evlist is the union of all the evsels cpus (ie not related to own_cpus as described here). Own_cpus I believe to be what's computed at parse-event time from sysfs. Is this a typo in the comment or quite likely my error?
Thanks, Ian
> + */ > bool system_wide; > + /* > + * Some events, for example uncore events, require a CPU. > + * i.e. it cannot be the 'any CPU' value of -1. > + */ > bool requires_cpu; > int idx; > }; > -- > 2.25.1 >
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