diff --git a/tools/perf/util/util.h b/tools/perf/util/util.h
index 2daaedb..b13c733 100644
--- a/tools/perf/util/util.h
+++ b/tools/perf/util/util.h
@@ -264,4 +264,6 @@
 
 size_t hex_width(u64 v);
 
+char *rtrim(char *s);
+
 #endif