[PATCH 2/2] perf stat: Show average value on multiple runs

[Namhyung Kim <namhyung@kernel.org>]

When -r option is used, perf stat runs the command multiple times and
update stats in the evsel->stats.res_stats for global aggregation.  But
the value is never used and the value it prints at the end is just the
value from the last run.  I think we should print the average number of
multiple runs.

Add evlist__copy_res_stats() to update the aggr counter (for display)
using the values in the evsel->stats.res_stats.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
---
 tools/perf/builtin-stat.c |  5 ++++-
 tools/perf/util/stat.c    | 22 ++++++++++++++++++++++
 tools/perf/util/stat.h    |  1 +
 3 files changed, 27 insertions(+), 1 deletion(-)

diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
index e549862f90f0..42f84975a4d5 100644
--- a/tools/perf/builtin-stat.c
+++ b/tools/perf/builtin-stat.c
@@ -2829,8 +2829,11 @@ int cmd_stat(int argc, const char **argv)
 		}
 	}
 
-	if (!forever && status != -1 && (!interval || stat_config.summary))
+	if (!forever && status != -1 && (!interval || stat_config.summary)) {
+		if (stat_config.run_count > 1)
+			evlist__copy_res_stats(&stat_config, evsel_list);
 		print_counters(NULL, argc, argv);
+	}
 
 	evlist__finalize_ctlfd(evsel_list);
 
diff --git a/tools/perf/util/stat.c b/tools/perf/util/stat.c
index 0f7b8a8cdea6..967e583392c7 100644
--- a/tools/perf/util/stat.c
+++ b/tools/perf/util/stat.c
@@ -264,6 +264,28 @@ void evlist__copy_prev_raw_counts(struct evlist *evlist)
 		evsel__copy_prev_raw_counts(evsel);
 }
 
+static void evsel__copy_res_stats(struct evsel *evsel)
+{
+	struct perf_stat_evsel *ps = evsel->stats;
+
+	/*
+	 * For GLOBAL aggregation mode, it updates the counts for each run
+	 * in the evsel->stats.res_stats.  See perf_stat_process_counter().
+	 */
+	*ps->aggr[0].counts.values = avg_stats(&ps->res_stats);
+}
+
+void evlist__copy_res_stats(struct perf_stat_config *config, struct evlist *evlist)
+{
+	struct evsel *evsel;
+
+	if (config->aggr_mode != AGGR_GLOBAL)
+		return;
+
+	evlist__for_each_entry(evlist, evsel)
+		evsel__copy_res_stats(evsel);
+}
+
 static size_t pkg_id_hash(long __key, void *ctx __maybe_unused)
 {
 	uint64_t *key = (uint64_t *) __key;
diff --git a/tools/perf/util/stat.h b/tools/perf/util/stat.h
index 7abff7cbb5a1..1cbc26b587ba 100644
--- a/tools/perf/util/stat.h
+++ b/tools/perf/util/stat.h
@@ -182,6 +182,7 @@ void evlist__save_aggr_prev_raw_counts(struct evlist *evlist);
 
 int evlist__alloc_aggr_stats(struct evlist *evlist, int nr_aggr);
 void evlist__reset_aggr_stats(struct evlist *evlist);
+void evlist__copy_res_stats(struct perf_stat_config *config, struct evlist *evlist);
 
 int perf_stat_process_counter(struct perf_stat_config *config,
 			      struct evsel *counter);
-- 
2.41.0.162.gfafddb0af9-goog