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>
---
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 ec3878c890a9..72aa6167c090 100644
--- a/tools/perf/util/pmu.c
+++ b/tools/perf/util/pmu.c
@@ -596,7 +596,7 @@ 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;
@@ -1884,9 +1884,10 @@ 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;
/**
--
2.34.1