Re: [PATCH v1] perf metrics: Remove the "No_group" metric group

[Ian Rogers]

On Wed, Apr 3, 2024 at 10:59 AM Liang, Kan <kan.liang@xxxxxxxxxxxxxxx> 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@xxxxxxxxxx>
> > ---
> >  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/metricgroup.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 struct pmu_metric *pm,
> >       const char *g;
> >       char *omg, *mg;
> >
> > -     mg = strdup(pm->metric_group ?: "No_group");
> > +     mg = strdup(pm->metric_group ?: pm->metric_name);
> >       if (!mg)
> >               return -ENOMEM;
> >       omg = mg;
> > @@ -466,7 +466,7 @@ static int metricgroup__add_to_mep_groups(const struct pmu_metric *pm,
> >               if (strlen(g))
> >                       me = mep_lookup(groups, g, pm->metric_name);
> >               else
> > -                     me = mep_lookup(groups, "No_group", pm->metric_name);
> > +                     me = mep_lookup(groups, pm->metric_name, pm->metric_name);
> >
> >               if (me) {
> >                       me->metric_desc = pm->desc;