From c9d699e10fa6c0cdabcddcf991e7ff42af6b2503 Mon Sep 17 00:00:00 2001 From: James Clark Date: Wed, 26 Feb 2025 10:41:01 +0000 Subject: [PATCH] perf pmu: Don't double count common sysfs and json events After pmu_add_cpu_aliases() is called, perf_pmu__num_events() returns an incorrect value that double counts common events and doesn't match the actual count of events in the alias list. This is because after 'cpu_aliases_added == true', the number of events returned is 'sysfs_aliases + cpu_json_aliases'. But when adding 'case EVENT_SRC_SYSFS' events, 'sysfs_aliases' and 'cpu_json_aliases' are both incremented together, failing to account that these ones overlap and only add a single item to the list. Fix it by adding another counter for overlapping events which doesn't influence 'cpu_json_aliases'. There doesn't seem to be a current issue because it's used in perf list before pmu_add_cpu_aliases() so the correct value is returned. Other uses in tests may also miss it for other reasons like only looking at uncore events. However it's marked as a fixes commit in case any new fix with new uses of perf_pmu__num_events() is backported. Fixes: d9c5f5f94c2d ("perf pmu: Count sys and cpuid JSON events separately") Reviewed-by: Ian Rogers Signed-off-by: James Clark Link: https://lore.kernel.org/r/20250226104111.564443-3-james.clark@linaro.org Signed-off-by: Namhyung Kim --- tools/perf/util/pmu.c | 7 ++++--- tools/perf/util/pmu.h | 5 +++++ 2 files changed, 9 insertions(+), 3 deletions(-) diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c index e51c17b1ea35..57450c73fb63 100644 --- a/tools/perf/util/pmu.c +++ b/tools/perf/util/pmu.c @@ -595,7 +595,7 @@ static int perf_pmu__new_alias(struct perf_pmu *pmu, const char *name, }; if (pmu_events_table__find_event(pmu->events_table, pmu, name, update_alias, &data) == 0) - pmu->cpu_json_aliases++; + pmu->cpu_common_json_aliases++; } pmu->sysfs_aliases++; break; @@ -1880,9 +1880,10 @@ size_t perf_pmu__num_events(struct perf_pmu *pmu) if (pmu->cpu_aliases_added) nr += pmu->cpu_json_aliases; else if (pmu->events_table) - nr += pmu_events_table__num_events(pmu->events_table, pmu) - pmu->cpu_json_aliases; + nr += pmu_events_table__num_events(pmu->events_table, pmu) - + pmu->cpu_common_json_aliases; else - assert(pmu->cpu_json_aliases == 0); + assert(pmu->cpu_json_aliases == 0 && pmu->cpu_common_json_aliases == 0); if (perf_pmu__is_tool(pmu)) nr -= tool_pmu__num_skip_events(); diff --git a/tools/perf/util/pmu.h b/tools/perf/util/pmu.h index f5306428c03f..b93014cc3670 100644 --- a/tools/perf/util/pmu.h +++ b/tools/perf/util/pmu.h @@ -136,6 +136,11 @@ struct perf_pmu { uint32_t cpu_json_aliases; /** @sys_json_aliases: Number of json event aliases loaded matching the PMU's identifier. */ uint32_t sys_json_aliases; + /** + * @cpu_common_json_aliases: Number of json events that overlapped with sysfs when + * loading all sysfs events. + */ + uint32_t cpu_common_json_aliases; /** @sysfs_aliases_loaded: Are sysfs aliases loaded from disk? */ bool sysfs_aliases_loaded; /** -- 2.50.1