Re: [PATCH v2 06/10] perf evsel: Add function to compute pmu_name

[Namhyung Kim <namhyung@kernel.org>]

On Thu, Mar 2, 2023 at 1:26 PM Ian Rogers <irogers@google.com> wrote:
>
> The computed pmu_name respects software events and aux event groups,
> such that the pmu_name is changed to be that of the aux event leader
> or group leader for software events. This is done as a later change
> will split events that are in different PMUs into different groups.
>
> Signed-off-by: Ian Rogers <irogers@google.com>
> ---
>  tools/perf/util/evsel.c | 24 ++++++++++++++++++++++++
>  tools/perf/util/evsel.h |  1 +
>  2 files changed, 25 insertions(+)
>
> diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
> index 2dc2c24252bb..9c6b486f8bd4 100644
> --- a/tools/perf/util/evsel.c
> +++ b/tools/perf/util/evsel.c
> @@ -821,6 +821,30 @@ const char *evsel__name(struct evsel *evsel)
>         return "unknown";
>  }
>
> +const char *evsel__pmu_name(const struct evsel *evsel)
> +{
> +       const struct evsel *leader;
> +
> +       /* If the pmu_name is set use it. pmu_name isn't set for CPU and software events. */
> +       if (evsel->pmu_name)
> +               return evsel->pmu_name;

I'm wondering if we can just use evsel->pmu->name if it's set.

> +       /*
> +        * Software events may be in a group with other uncore PMU events. Use
> +        * the pmu_name of the group leader to avoid breaking the software event
> +        * out of the group.
> +        *
> +        * Aux event leaders, like intel_pt, expect a group with events from
> +        * other PMUs, so substitute the AUX event's PMU in this case.
> +        */

Looks like we need to rename this function as it doesn't simply return
the pmu name in the above cases.  Maybe evsel__group_pmu_name() ?

Thanks,
Namhyung


> +       leader  = evsel__leader(evsel);
> +       if ((evsel->core.attr.type == PERF_TYPE_SOFTWARE || evsel__is_aux_event(leader)) &&
> +           leader->pmu_name) {
> +               return leader->pmu_name;
> +       }
> +
> +       return "cpu";
> +}
> +
>  const char *evsel__metric_id(const struct evsel *evsel)
>  {
>         if (evsel->metric_id)
> diff --git a/tools/perf/util/evsel.h b/tools/perf/util/evsel.h
> index 676c499323e9..72121194d3b1 100644
> --- a/tools/perf/util/evsel.h
> +++ b/tools/perf/util/evsel.h
> @@ -280,6 +280,7 @@ int arch_evsel__hw_name(struct evsel *evsel, char *bf, size_t size);
>
>  int __evsel__hw_cache_type_op_res_name(u8 type, u8 op, u8 result, char *bf, size_t size);
>  const char *evsel__name(struct evsel *evsel);
> +const char *evsel__pmu_name(const struct evsel *evsel);
>  const char *evsel__metric_id(const struct evsel *evsel);
>
>  static inline bool evsel__is_tool(const struct evsel *evsel)
> --
> 2.40.0.rc0.216.gc4246ad0f0-goog
>