diff --git a/tools/perf/builtin-ftrace.c b/tools/perf/builtin-ftrace.c
index eb30c8eca488..8eab3cdb2c6d 100644
--- a/tools/perf/builtin-ftrace.c
+++ b/tools/perf/builtin-ftrace.c
@@ -771,7 +771,7 @@ static void display_histogram(int buckets[], bool use_nsec)
 
 	bar_len = buckets[0] * bar_total / total;
 	printf("  %4d - %-4d %s | %10d | %.*s%*s |\n",
-	       0, 1, "us", buckets[0], bar_len, bar, bar_total - bar_len, "");
+	       0, 1, use_nsec ? "ns" : "us", buckets[0], bar_len, bar, bar_total - bar_len, "");
 
 	for (i = 1; i < NUM_BUCKET - 1; i++) {
 		int start = (1 << (i - 1));