Messages in this thread | | | From | Ian Rogers <> | Date | Thu, 5 May 2022 17:01:50 -0700 | Subject | Re: [PATCH V1 16/23] perf intel-pt: Track sideband system-wide when needed |
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On Thu, May 5, 2022 at 9:58 AM Adrian Hunter <adrian.hunter@intel.com> wrote: > > User space tasks can migrate between CPUs, so when tracing selected CPUs, > sideband for all CPUs is still needed. This is in preparation for allowing > system-wide events on all CPUs while the user requested events are on only > user requested CPUs. > > Signed-off-by: Adrian Hunter <adrian.hunter@intel.com> > --- > tools/perf/arch/x86/util/intel-pt.c | 18 ++++++++++-------- > 1 file changed, 10 insertions(+), 8 deletions(-) > > diff --git a/tools/perf/arch/x86/util/intel-pt.c b/tools/perf/arch/x86/util/intel-pt.c > index e45d64dec57c..62be78bc90b6 100644 > --- a/tools/perf/arch/x86/util/intel-pt.c > +++ b/tools/perf/arch/x86/util/intel-pt.c > @@ -864,20 +864,22 @@ static int intel_pt_recording_options(struct auxtrace_record *itr, > > /* Add dummy event to keep tracking */ > if (opts->full_auxtrace) { > + bool need_system_wide_tracking;
Nit: perhaps need_dummy_on_all_online_cpus
Acked-by: Ian Rogers <irogers@google.com>
Thanks, Ian
> struct evsel *tracking_evsel; > > - err = parse_events(evlist, "dummy:u", NULL); > - if (err) > - return err; > + /* > + * User space tasks can migrate between CPUs, so when tracing > + * selected CPUs, sideband for all CPUs is still needed. > + */ > + need_system_wide_tracking = evlist->core.has_user_cpus && > + !intel_pt_evsel->core.attr.exclude_user; > > - tracking_evsel = evlist__last(evlist); > + tracking_evsel = evlist__add_aux_dummy(evlist, need_system_wide_tracking); > + if (!tracking_evsel) > + return -ENOMEM; > > evlist__set_tracking_event(evlist, tracking_evsel); > > - tracking_evsel->core.attr.freq = 0; > - tracking_evsel->core.attr.sample_period = 1; > - > - tracking_evsel->no_aux_samples = true; > if (need_immediate) > tracking_evsel->immediate = true; > > -- > 2.25.1 >
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