Re: [PATCH v6 1/7] perf evlist: Add perf_evlist__go_system_wide() helper

[Ian Rogers]

On Sun, Aug 20, 2023 at 6:30 PM Yang Jihong <yangjihong1@xxxxxxxxxx> wrote:
>
> For dummy events that keep tracking, we may need to modify its cpu_maps.
> For example, change the cpu_maps to record sideband events for all CPUS.
> Add perf_evlist__go_system_wide() helper to support this scenario.
>
> Signed-off-by: Yang Jihong <yangjihong1@xxxxxxxxxx>
> Acked-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>
> ---
>  tools/lib/perf/evlist.c                  | 9 +++++++++
>  tools/lib/perf/include/internal/evlist.h | 2 ++
>  2 files changed, 11 insertions(+)
>
> diff --git a/tools/lib/perf/evlist.c b/tools/lib/perf/evlist.c
> index b8b066d0dc5e..3acbbccc1901 100644
> --- a/tools/lib/perf/evlist.c
> +++ b/tools/lib/perf/evlist.c
> @@ -738,3 +738,12 @@ int perf_evlist__nr_groups(struct perf_evlist *evlist)
>         }
>         return nr_groups;
>  }
> +
> +void perf_evlist__go_system_wide(struct perf_evlist *evlist, struct perf_evsel *evsel)
> +{
> +       if (!evsel->system_wide) {
> +               evsel->system_wide = true;
> +               if (evlist->needs_map_propagation)
> +                       __perf_evlist__propagate_maps(evlist, evsel);
> +       }
> +}

I think this should be:

void evsel__set_system_wide(struct evsel *evsel)
{
        if (evsel->system_wide)
               return;
        evsel->system_wide = true;
        if (evsel->evlist->core.needs_map_propagation)
...

The API being on evlist makes it look like all evsels are affected.

Thanks,
Ian

> diff --git a/tools/lib/perf/include/internal/evlist.h b/tools/lib/perf/include/internal/evlist.h
> index 3339bc2f1765..d86ffe8ed483 100644
> --- a/tools/lib/perf/include/internal/evlist.h
> +++ b/tools/lib/perf/include/internal/evlist.h
> @@ -135,4 +135,6 @@ int perf_evlist__id_add_fd(struct perf_evlist *evlist,
>  void perf_evlist__reset_id_hash(struct perf_evlist *evlist);
>
>  void __perf_evlist__set_leader(struct list_head *list, struct perf_evsel *leader);
> +
> +void perf_evlist__go_system_wide(struct perf_evlist *evlist, struct perf_evsel *evsel);
>  #endif /* __LIBPERF_INTERNAL_EVLIST_H */
> --
> 2.30.GIT
>