[PATCH v4 33/35] perf pmus: Add function to return count of core PMUs

[Ian Rogers]

Add perf_pmus__num_core_pmus that will count core PMUs holding the
result in a static. Reuse for perf_pmus__num_mem_pmus.

Signed-off-by: Ian Rogers <irogers@xxxxxxxxxx>
Reviewed-by: Kan Liang <kan.liang@xxxxxxxxxxxxxxx>
---
 tools/perf/util/pmus.c | 21 ++++++++++++++-------
 tools/perf/util/pmus.h |  1 +
 2 files changed, 15 insertions(+), 7 deletions(-)

diff --git a/tools/perf/util/pmus.c b/tools/perf/util/pmus.c
index 6ecccb5ad03e..bf927aed162e 100644
--- a/tools/perf/util/pmus.c
+++ b/tools/perf/util/pmus.c
@@ -229,14 +229,8 @@ const struct perf_pmu *perf_pmus__pmu_for_pmu_filter(const char *str)
 
 int perf_pmus__num_mem_pmus(void)
 {
-	struct perf_pmu *pmu = NULL;
-	int count = 0;
-
 	/* All core PMUs are for mem events. */
-	while ((pmu = perf_pmus__scan_core(pmu)) != NULL)
-		count++;
-
-	return count;
+	return perf_pmus__num_core_pmus();
 }
 
 /** Struct for ordering events as output in perf list. */
@@ -488,6 +482,19 @@ bool perf_pmus__has_hybrid(void)
 	return has_hybrid;
 }
 
+int perf_pmus__num_core_pmus(void)
+{
+	static int count;
+
+	if (!count) {
+		struct perf_pmu *pmu = NULL;
+
+		while ((pmu = perf_pmus__scan_core(pmu)) != NULL)
+			count++;
+	}
+	return count;
+}
+
 struct perf_pmu *evsel__find_pmu(const struct evsel *evsel)
 {
 	struct perf_pmu *pmu = evsel->pmu;
diff --git a/tools/perf/util/pmus.h b/tools/perf/util/pmus.h
index 9de0222ed52b..27400a027d41 100644
--- a/tools/perf/util/pmus.h
+++ b/tools/perf/util/pmus.h
@@ -19,5 +19,6 @@ int perf_pmus__num_mem_pmus(void);
 void perf_pmus__print_pmu_events(const struct print_callbacks *print_cb, void *print_state);
 bool perf_pmus__have_event(const char *pname, const char *name);
 bool perf_pmus__has_hybrid(void);
+int perf_pmus__num_core_pmus(void);
 
 #endif /* __PMUS_H */
-- 
2.41.0.rc0.172.g3f132b7071-goog