diff --git a/tools/perf/Documentation/perf-stat.txt b/tools/perf/Documentation/perf-stat.txt
index 4d56586b2fb926232ac754b7485c4dc041525d4e..3fb5028aef089c2bff4d76005c9be45fa72d7d21 100644
--- a/tools/perf/Documentation/perf-stat.txt
+++ b/tools/perf/Documentation/perf-stat.txt
@@ -176,6 +176,8 @@ Print count deltas every N milliseconds (minimum: 1ms)
 The overhead percentage could be high in some cases, for instance with small, sub 100ms intervals.  Use with caution.
 	example: 'perf stat -I 1000 -e cycles -a sleep 5'
 
+If the metric exists, it is calculated by the counts generated in this interval and the metric is printed after #.
+
 --interval-count times::
 Print count deltas for fixed number of times.
 This option should be used together with "-I" option.
diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
index 9207b6c4547562a0110350bb2e70aeb8368d675a..3f050d85c277ded8d7eebaa7bd911f4eeb54125d 100644
--- a/tools/perf/builtin-stat.c
+++ b/tools/perf/builtin-stat.c
@@ -359,6 +359,7 @@ static void process_interval(void)
 	clock_gettime(CLOCK_MONOTONIC, &ts);
 	diff_timespec(&rs, &ts, &ref_time);
 
+	perf_stat__reset_shadow_per_stat(&rt_stat);
 	read_counters(&rs);
 
 	if (STAT_RECORD) {