Re: [PATCH 15/19] perf stat: Add perf_stat_process_percore()

[Ian Rogers]

On Sun, Oct 9, 2022 at 10:36 PM Namhyung Kim <namhyung@xxxxxxxxxx> wrote:
>
> The perf_stat_process_percore() is to aggregate counts for an event per-core
> even if the aggr_mode is AGGR_NONE.  This is enabled when user requested it
> on the command line.

Is there an example command line for this? It would be nice to add as a test.

Thanks,
Ian

> To handle that, it keeps the per-cpu counts at first.  And then it aggregates
> the counts that have the same core id in the aggr->counts and updates the
> values for each cpu back.
>
> Later, per-core events will skip one of the CPUs unless percore-show-thread
> option is given.  In that case, it can simply print all cpu stats with the
> updated (per-core) values.
>
> Signed-off-by: Namhyung Kim <namhyung@xxxxxxxxxx>
> ---
>  tools/perf/builtin-stat.c |  1 +
>  tools/perf/util/stat.c    | 71 +++++++++++++++++++++++++++++++++++++++
>  tools/perf/util/stat.h    |  2 ++
>  3 files changed, 74 insertions(+)
>
> diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
> index f90e8f29cb23..c127e784a7be 100644
> --- a/tools/perf/builtin-stat.c
> +++ b/tools/perf/builtin-stat.c
> @@ -488,6 +488,7 @@ static void process_counters(void)
>         }
>
>         perf_stat_merge_counters(&stat_config, evsel_list);
> +       perf_stat_process_percore(&stat_config, evsel_list);
>  }
>
>  static void process_interval(void)
> diff --git a/tools/perf/util/stat.c b/tools/perf/util/stat.c
> index 1bb197782a34..d788d0e85204 100644
> --- a/tools/perf/util/stat.c
> +++ b/tools/perf/util/stat.c
> @@ -671,6 +671,77 @@ void perf_stat_merge_counters(struct perf_stat_config *config, struct evlist *ev
>                 evsel__merge_stats(evsel, config);
>  }
>
> +static void evsel__update_percore_stats(struct evsel *evsel, struct aggr_cpu_id *core_id)
> +{
> +       struct perf_stat_evsel *ps = evsel->stats;
> +       struct perf_counts_values counts = { 0, };
> +       struct aggr_cpu_id id;
> +       struct perf_cpu cpu;
> +       int idx;
> +
> +       /* collect per-core counts */
> +       perf_cpu_map__for_each_cpu(cpu, idx, evsel->core.cpus) {
> +               struct perf_stat_aggr *aggr = &ps->aggr[idx];
> +
> +               id = aggr_cpu_id__core(cpu, NULL);
> +               if (!aggr_cpu_id__equal(core_id, &id))
> +                       continue;
> +
> +               counts.val += aggr->counts.val;
> +               counts.ena += aggr->counts.ena;
> +               counts.run += aggr->counts.run;
> +       }
> +
> +       /* update aggregated per-core counts for each CPU */
> +       perf_cpu_map__for_each_cpu(cpu, idx, evsel->core.cpus) {
> +               struct perf_stat_aggr *aggr = &ps->aggr[idx];
> +
> +               id = aggr_cpu_id__core(cpu, NULL);
> +               if (!aggr_cpu_id__equal(core_id, &id))
> +                       continue;
> +
> +               aggr->counts.val = counts.val;
> +               aggr->counts.ena = counts.ena;
> +               aggr->counts.run = counts.run;
> +
> +               aggr->used = true;
> +       }
> +}
> +
> +/* we have an aggr_map for cpu, but want to aggregate the counters per-core */
> +static void evsel__process_percore(struct evsel *evsel)
> +{
> +       struct perf_stat_evsel *ps = evsel->stats;
> +       struct aggr_cpu_id core_id;
> +       struct perf_cpu cpu;
> +       int idx;
> +
> +       if (!evsel->percore)
> +               return;
> +
> +       perf_cpu_map__for_each_cpu(cpu, idx, evsel->core.cpus) {
> +               struct perf_stat_aggr *aggr = &ps->aggr[idx];
> +
> +               if (aggr->used)
> +                       continue;
> +
> +               core_id = aggr_cpu_id__core(cpu, NULL);
> +               evsel__update_percore_stats(evsel, &core_id);
> +       }
> +}
> +
> +/* process cpu stats on per-core events */
> +void perf_stat_process_percore(struct perf_stat_config *config, struct evlist *evlist)
> +{
> +       struct evsel *evsel;
> +
> +       if (config->aggr_mode != AGGR_NONE)
> +               return;
> +
> +       evlist__for_each_entry(evlist, evsel)
> +               evsel__process_percore(evsel);
> +}
> +
>  int perf_event__process_stat_event(struct perf_session *session,
>                                    union perf_event *event)
>  {
> diff --git a/tools/perf/util/stat.h b/tools/perf/util/stat.h
> index 12cc60ab04e4..ac85ed46aa59 100644
> --- a/tools/perf/util/stat.h
> +++ b/tools/perf/util/stat.h
> @@ -46,6 +46,7 @@ enum perf_stat_evsel_id {
>  struct perf_stat_aggr {
>         struct perf_counts_values       counts;
>         int                             nr;
> +       bool                            used;
>         bool                            failed;
>  };
>
> @@ -271,6 +272,7 @@ void evlist__reset_aggr_stats(struct evlist *evlist);
>  int perf_stat_process_counter(struct perf_stat_config *config,
>                               struct evsel *counter);
>  void perf_stat_merge_counters(struct perf_stat_config *config, struct evlist *evlist);
> +void perf_stat_process_percore(struct perf_stat_config *config, struct evlist *evlist);
>
>  struct perf_tool;
>  union perf_event;
> --
> 2.38.0.rc1.362.ged0d419d3c-goog
>