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From: Ian Rogers <irogers@google.com>
Date: Wed, 3 Apr 2024 11:31:37 -0700
Message-ID: <CAP-5=fUgiafmLEKEUJ5r5_tK+jqv30P0TGFCMvR8DkW7J4qYsQ@mail.gmail.com>
Subject: Re: [PATCH v1] perf metrics: Remove the "No_group" metric group
To: "Liang, Kan" <kan.liang@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>, Ingo Molnar <mingo@redhat.com>, 
	Arnaldo Carvalho de Melo <acme@kernel.org>, Namhyung Kim <namhyung@kernel.org>, 
	Mark Rutland <mark.rutland@arm.com>, 
	Alexander Shishkin <alexander.shishkin@linux.intel.com>, Jiri Olsa <jolsa@kernel.org>, 
	Adrian Hunter <adrian.hunter@intel.com>, linux-perf-users@vger.kernel.org, 
	linux-kernel@vger.kernel.org, Andi Kleen <ak@linux.intel.com>
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On Wed, Apr 3, 2024 at 10:59=E2=80=AFAM Liang, Kan <kan.liang@linux.intel.c=
om> wrote:
>
>
>
> On 2024-04-03 12:46 p.m., Ian Rogers wrote:
> > Rather than place metrics without a metric group in "No_group" place
> > them in a a metric group that is their name. Still allow such metrics
> > to be selected if "No_group" is passed, this change just impacts perf
> > list.
>
> So it looks like the "No_group" is not completely removed.
> They are just not seen in the perf list, but users can still use it via
> perf stat -M No_group, right?
>
> If so, why we want to remove it from perf list? Where can the end user
> know which metrics are included in the No_group?
>
> If the No_group is useless, why not completely remove it?

Agreed. For command line argument deprecation we usually keep the
option but hide it from help with PARSE_OPT_HIDDEN, so I was trying to
follow that pattern albeit that a metric group isn't a command line
option it's an option to an option.

Thanks,
Ian

> Thanks,
> Kan
>
> >
> > Signed-off-by: Ian Rogers <irogers@google.com>
> > ---
> >  tools/perf/util/metricgroup.c | 4 ++--
> >  1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/tools/perf/util/metricgroup.c b/tools/perf/util/metricgrou=
p.c
> > index 79ef6095ab28..6ec083af14a1 100644
> > --- a/tools/perf/util/metricgroup.c
> > +++ b/tools/perf/util/metricgroup.c
> > @@ -455,7 +455,7 @@ static int metricgroup__add_to_mep_groups(const str=
uct pmu_metric *pm,
> >       const char *g;
> >       char *omg, *mg;
> >
> > -     mg =3D strdup(pm->metric_group ?: "No_group");
> > +     mg =3D strdup(pm->metric_group ?: pm->metric_name);
> >       if (!mg)
> >               return -ENOMEM;
> >       omg =3D mg;
> > @@ -466,7 +466,7 @@ static int metricgroup__add_to_mep_groups(const str=
uct pmu_metric *pm,
> >               if (strlen(g))
> >                       me =3D mep_lookup(groups, g, pm->metric_name);
> >               else
> > -                     me =3D mep_lookup(groups, "No_group", pm->metric_=
name);
> > +                     me =3D mep_lookup(groups, pm->metric_name, pm->me=
tric_name);
> >
> >               if (me) {
> >                       me->metric_desc =3D pm->desc;