Re: [PATCH v2 1/2] perf evlist: Ensure grouped events with same cpu map

Jiri Olsa
2020-05-26T11:52:06Z

On Mon, May 25, 2020 at 02:55:58PM +0800, Jin Yao wrote:

SNIP

> diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
> index 2a9de6491700..1161cffc0688 100644
> --- a/tools/perf/util/evlist.c
> +++ b/tools/perf/util/evlist.c
> @@ -1704,3 +1704,52 @@ struct evsel *perf_evlist__reset_weak_group(struct evlist *evsel_list,
> }
> return leader;
> }
> +
> +static bool cpus_map_matched(struct evsel *prev, struct evsel *evsel)
> +{
> + if (evsel->core.cpus->nr != prev->core.cpus->nr)
> + return false;
> +
> + for (int i = 0; i < evsel->core.cpus->nr; i++) {
> + if (evsel->core.cpus->map[i] != prev->core.cpus->map[i])
> + return false;
> + }
> +
> + return true;
> +}
> +
> +bool evlist__cpus_map_matched(struct evlist *evlist)
> +{
> + struct evsel *prev = evlist__first(evlist), *evsel = prev;
> + int nr_members = prev->core.nr_members;
> +
> + evlist__for_each_entry_continue(evlist, evsel) {
> + if (nr_members <= 1) {
> + prev = evsel;
> + nr_members = evsel->core.nr_members;
> + continue;
> + }
> +
> + nr_members--;
> +
> + if (!cpus_map_matched(prev, evsel))
> + return false;
> +
> + prev = evsel;
> + }
> +
> + return true;
> +}
> +
> +void evlist__force_disable_group(struct evlist *evlist)
> +{
> + struct evsel *evsel;
> +
> + pr_warning("WARNING: event cpu maps are not fully matched, "
> + "stop event grouping\n");
> +
> + evlist__for_each_entry(evlist, evsel) {
> + evsel->leader = evsel;
> + evsel->core.nr_members = 0;
> + }
> +}

I think this is too much, we need to disable only groups with not
matching cpus, not all of them, how about something like this

struct evsel *pos;

evlist__for_each_entry(evlist, evsel) {
if (evsel->leader == evsel)
continue;
if (!cpus_map_matched(evsel->leader, evsel))
continue;

pr_warn("Disabling group...

for_each_group_member(pos, evsel->leader) {
pos->leader = pos;
evsel->core.nr_members = 0;
}
}

jirka