diff options
| author | James Clark <james.clark@linaro.org> | 2025-02-26 10:41:01 +0000 |
|---|---|---|
| committer | Namhyung Kim <namhyung@kernel.org> | 2025-02-26 16:23:47 -0800 |
| commit | c9d699e10fa6c0cdabcddcf991e7ff42af6b2503 (patch) | |
| tree | de2b32ec5b93be3e305b5feb4698ceb7cd701fb1 | |
| parent | 72c6f57a4193f2eadceb52261315438719c4c1ad (diff) | |
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 <irogers@google.com>
Signed-off-by: James Clark <james.clark@linaro.org>
Link: https://lore.kernel.org/r/20250226104111.564443-3-james.clark@linaro.org
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
| -rw-r--r-- | tools/perf/util/pmu.c | 7 | ||||
| -rw-r--r-- | 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; /** |