diff --git a/tools/perf/util/hist.c b/tools/perf/util/hist.c
index 02476cb..277947a 100644
--- a/tools/perf/util/hist.c
+++ b/tools/perf/util/hist.c
@@ -151,6 +151,22 @@
 	}
 }
 
+static void he_stat__add_period(struct he_stat *he_stat, u64 period)
+{
+	he_stat->period		+= period;
+	he_stat->nr_events	+= 1;
+}
+
+static void he_stat__add_stat(struct he_stat *dest, struct he_stat *src)
+{
+	dest->period		+= src->period;
+	dest->period_sys	+= src->period_sys;
+	dest->period_us		+= src->period_us;
+	dest->period_guest_sys	+= src->period_guest_sys;
+	dest->period_guest_us	+= src->period_guest_us;
+	dest->nr_events		+= src->nr_events;
+}
+
 static void hist_entry__decay(struct hist_entry *he)
 {
 	he->stat.period = (he->stat.period * 7) / 8;
@@ -270,8 +286,7 @@
 		cmp = hist_entry__cmp(entry, he);
 
 		if (!cmp) {
-			he->stat.period += period;
-			++he->stat.nr_events;
+			he_stat__add_period(&he->stat, period);
 
 			/* If the map of an existing hist_entry has
 			 * become out-of-date due to an exec() or
@@ -418,12 +433,7 @@
 		cmp = hist_entry__collapse(iter, he);
 
 		if (!cmp) {
-			iter->stat.period		+= he->stat.period;
-			iter->stat.period_sys		+= he->stat.period_sys;
-			iter->stat.period_us		+= he->stat.period_us;
-			iter->stat.period_guest_sys	+= he->stat.period_guest_sys;
-			iter->stat.period_guest_us	+= he->stat.period_guest_us;
-			iter->stat.nr_events		+= he->stat.nr_events;
+			he_stat__add_stat(&iter->stat, &he->stat);
 
 			if (symbol_conf.use_callchain) {
 				callchain_cursor_reset(&callchain_cursor);