linux-kernel - Re: [PATCH v1 04/10] perf stat: Modify the group test

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Message-ID: <CAP-5=fVTviA3y0rLWUOs=WkB5B1Fw_dd9PMZXBhLN38c5F_u3Q@mail.gmail.com>
Date:   Thu, 2 Mar 2023 08:10:08 -0800
From:   Ian Rogers <irogers@...gle.com>
To:     Arnaldo Carvalho de Melo <acme@...nel.org>
Cc:     Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...hat.com>,
        Mark Rutland <mark.rutland@....com>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Jiri Olsa <jolsa@...nel.org>,
        Namhyung Kim <namhyung@...nel.org>,
        Kan Liang <kan.liang@...ux.intel.com>,
        Zhengjun Xing <zhengjun.xing@...ux.intel.com>,
        Ravi Bangoria <ravi.bangoria@....com>,
        Adrian Hunter <adrian.hunter@...el.com>,
        "Steinar H. Gunderson" <sesse@...gle.com>,
        Qi Liu <liuqi115@...wei.com>,
        Kim Phillips <kim.phillips@....com>,
        Florian Fischer <florian.fischer@...q.space>,
        James Clark <james.clark@....com>,
        Suzuki Poulouse <suzuki.poulose@....com>,
        Sean Christopherson <seanjc@...gle.com>,
        Leo Yan <leo.yan@...aro.org>,
        John Garry <john.g.garry@...cle.com>,
        Kajol Jain <kjain@...ux.ibm.com>,
        linux-perf-users@...r.kernel.org, linux-kernel@...r.kernel.org,
        Stephane Eranian <eranian@...gle.com>
Subject: Re: [PATCH v1 04/10] perf stat: Modify the group test

On Thu, Mar 2, 2023 at 6:34 AM Arnaldo Carvalho de Melo <acme@...nel.org> wrote:
>
> Em Wed, Mar 01, 2023 at 08:12:05PM -0800, Ian Rogers escreveu:
> > Previously nr_members would be 0 for an event with no group. The
> > previous change made that count 1, the event is its own leader without
> > a group. Make the find_stat logic consistent with this, an improvement
> > suggested by Namhyung Kim.
>
> Is this the only place where this change in behaviour needs to be taken
> into account?
>
> - Arnaldo

Actually, I reordered the patches and so the review comment is off.
The nr_members change is in the sorting patch 9. I'll fix up the
comment. I did look for other uses and didn't spot any. I also think
we can add some kind of helper. The current evsel__is_leader functions
are weird. When thinking about the helper I couldn't think of a good
name as I want groups greater than size 1. I'll tweak this.

Thanks,
Ian

> > Suggested-by: Namhyung Kim <namhyung@...nel.org>
> > Signed-off-by: Ian Rogers <irogers@...gle.com>
> > ---
> >  tools/perf/util/stat-shadow.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/tools/perf/util/stat-shadow.c b/tools/perf/util/stat-shadow.c
> > index ef85f1ae1ab2..eeccab6751d7 100644
> > --- a/tools/perf/util/stat-shadow.c
> > +++ b/tools/perf/util/stat-shadow.c
> > @@ -163,7 +163,7 @@ static double find_stat(const struct evsel *evsel, int aggr_idx, enum stat_type
> >                       continue;
> >
> >               /* Ignore evsels that are part of different groups. */
> > -             if (evsel->core.leader->nr_members &&
> > +             if (evsel->core.leader->nr_members > 1 &&
> >                   evsel->core.leader != cur->core.leader)
> >                       continue;
> >               /* Ignore evsels with mismatched modifiers. */
> > --
> > 2.39.2.722.g9855ee24e9-goog
> >
>
> --
>
> - Arnaldo