diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
index 89655d53117a..74a2cafb4e8d 100644
--- a/tools/perf/util/pmu.c
+++ b/tools/perf/util/pmu.c
@@ -1182,7 +1182,7 @@ static char *pmu_formats_string(struct list_head *formats)
 	struct perf_pmu_format *format;
 	char *str = NULL;
 	struct strbuf buf = STRBUF_INIT;
-	unsigned i = 0;
+	unsigned int i = 0;
 
 	if (!formats)
 		return NULL;