linux-kernel - Re: [PATCH 2/2] perf x86/topdown: Refine helper arch_is_topdown

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Message-ID: <CAP-5=fWfRwxWsgqD8OUG8+2WrU5Xg+ByqGAbLED9Wf3ZQ=FURw@mail.gmail.com>
Date: Wed, 16 Oct 2024 10:55:33 -0700
From: Ian Rogers <irogers@...gle.com>
To: Namhyung Kim <namhyung@...nel.org>
Cc: Dapeng Mi <dapeng1.mi@...ux.intel.com>, Peter Zijlstra <peterz@...radead.org>, 
	Ingo Molnar <mingo@...hat.com>, Arnaldo Carvalho de Melo <acme@...nel.org>, 
	Adrian Hunter <adrian.hunter@...el.com>, 
	Alexander Shishkin <alexander.shishkin@...ux.intel.com>, Kan Liang <kan.liang@...ux.intel.com>, 
	linux-perf-users@...r.kernel.org, linux-kernel@...r.kernel.org, 
	Dapeng Mi <dapeng1.mi@...el.com>
Subject: Re: [PATCH 2/2] perf x86/topdown: Refine helper arch_is_topdown_metrics()

On Wed, Oct 16, 2024 at 10:37 AM Namhyung Kim <namhyung@...nel.org> wrote:
>
> Hi Ian,
>
> On Fri, Oct 11, 2024 at 11:02:07AM +0000, Dapeng Mi wrote:
> > Leverage the existed function perf_pmu__name_from_config() to check if
> > an event is topdown metrics event. perf_pmu__name_from_config() goes
> > through the defined formats and figures out the config of pre-defined
> > topdown events.
> >
> > This avoids to figure out the config of topdown pre-defined events with
> > hard-coded format strings "event=" and "umask=" and provides more
> > flexibility.
> >
> > Suggested-by: Ian Rogers <irogers@...gle.com>
> > Signed-off-by: Dapeng Mi <dapeng1.mi@...ux.intel.com>
>
> Are you ok with this now?

Reviewed-by: Ian Rogers <irogers@...gle.com>

Thanks,
Ian

> Thanks,
> Namhyung
>
> > ---
> >  tools/perf/arch/x86/util/topdown.c | 39 +++++++-----------------------
> >  1 file changed, 9 insertions(+), 30 deletions(-)
> >
> > diff --git a/tools/perf/arch/x86/util/topdown.c b/tools/perf/arch/x86/util/topdown.c
> > index cb2c64928bc4..f63747d0abdf 100644
> > --- a/tools/perf/arch/x86/util/topdown.c
> > +++ b/tools/perf/arch/x86/util/topdown.c
> > @@ -41,43 +41,22 @@ bool arch_is_topdown_slots(const struct evsel *evsel)
> >       return false;
> >  }
> >
> > -static int compare_topdown_event(void *vstate, struct pmu_event_info *info)
> > -{
> > -     int *config = vstate;
> > -     int event = 0;
> > -     int umask = 0;
> > -     char *str;
> > -
> > -     if (!strcasestr(info->name, "topdown"))
> > -             return 0;
> > -
> > -     str = strcasestr(info->str, "event=");
> > -     if (str)
> > -             sscanf(str, "event=%x", &event);
> > -
> > -     str = strcasestr(info->str, "umask=");
> > -     if (str)
> > -             sscanf(str, "umask=%x", &umask);
> > -
> > -     if (event == 0 && *config == (event | umask << 8))
> > -             return 1;
> > -
> > -     return 0;
> > -}
> > -
> >  bool arch_is_topdown_metrics(const struct evsel *evsel)
> >  {
> > -     struct perf_pmu *pmu = evsel__find_pmu(evsel);
> >       int config = evsel->core.attr.config;
> > +     const char *name_from_config;
> > +     struct perf_pmu *pmu;
> >
> > -     if (!pmu || !pmu->is_core)
> > +     /* All topdown events have an event code of 0. */
> > +     if ((config & 0xFF) != 0)
> >               return false;
> >
> > -     if (perf_pmu__for_each_event(pmu, false, &config,
> > -                                  compare_topdown_event))
> > -             return true;
> > +     pmu = evsel__find_pmu(evsel);
> > +     if (!pmu || !pmu->is_core)
> > +             return false;
> >
> > -     return false;
> > +     name_from_config = perf_pmu__name_from_config(pmu, config);
> > +     return name_from_config && strcasestr(name_from_config, "topdown");
> >  }
> >
> >  /*
> > --
> > 2.40.1
> >