[PATCH 1/2] libperf: Add perf_evlist__reset_id_hash()

[Namhyung Kim <namhyung@kernel.org>]

Add the perf_evlist__reset_id_hash() function to libperf API so that
it can be called to reset the hash table.  This is necessary for perf
stat to run the workload multiple times.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
---
 tools/lib/perf/evlist.c              | 13 +++++++++----
 tools/lib/perf/include/perf/evlist.h |  2 ++
 tools/lib/perf/libperf.map           |  1 +
 3 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/tools/lib/perf/evlist.c b/tools/lib/perf/evlist.c
index 17465d454a0e..a0aaf385cbb5 100644
--- a/tools/lib/perf/evlist.c
+++ b/tools/lib/perf/evlist.c
@@ -26,13 +26,10 @@
 
 void perf_evlist__init(struct perf_evlist *evlist)
 {
-	int i;
-
-	for (i = 0; i < PERF_EVLIST__HLIST_SIZE; ++i)
-		INIT_HLIST_HEAD(&evlist->heads[i]);
 	INIT_LIST_HEAD(&evlist->entries);
 	evlist->nr_entries = 0;
 	fdarray__init(&evlist->pollfd, 64);
+	perf_evlist__reset_id_hash(evlist);
 }
 
 static void __perf_evlist__propagate_maps(struct perf_evlist *evlist,
@@ -237,6 +234,14 @@ static void perf_evlist__id_hash(struct perf_evlist *evlist,
 	hlist_add_head(&sid->node, &evlist->heads[hash]);
 }
 
+void perf_evlist__reset_id_hash(struct perf_evlist *evlist)
+{
+	int i;
+
+	for (i = 0; i < PERF_EVLIST__HLIST_SIZE; ++i)
+		INIT_HLIST_HEAD(&evlist->heads[i]);
+}
+
 void perf_evlist__id_add(struct perf_evlist *evlist,
 			 struct perf_evsel *evsel,
 			 int cpu, int thread, u64 id)
diff --git a/tools/lib/perf/include/perf/evlist.h b/tools/lib/perf/include/perf/evlist.h
index 0a7479dc13bf..0085732e8cd9 100644
--- a/tools/lib/perf/include/perf/evlist.h
+++ b/tools/lib/perf/include/perf/evlist.h
@@ -46,4 +46,6 @@ LIBPERF_API struct perf_mmap *perf_evlist__next_mmap(struct perf_evlist *evlist,
 	     (pos) != NULL;						\
 	     (pos) = perf_evlist__next_mmap((evlist), (pos), overwrite))
 
+LIBPERF_API void perf_evlist__reset_id_hash(struct perf_evlist *evlist);
+
 #endif /* __LIBPERF_EVLIST_H */
diff --git a/tools/lib/perf/libperf.map b/tools/lib/perf/libperf.map
index 7be1af8a546c..285100143d89 100644
--- a/tools/lib/perf/libperf.map
+++ b/tools/lib/perf/libperf.map
@@ -42,6 +42,7 @@ LIBPERF_0.0.1 {
 		perf_evlist__munmap;
 		perf_evlist__filter_pollfd;
 		perf_evlist__next_mmap;
+		perf_evlist__reset_id_hash;
 		perf_mmap__consume;
 		perf_mmap__read_init;
 		perf_mmap__read_done;
-- 
2.30.0.617.g56c4b15f3c-goog