diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
index 0b5425b..07ba0a4 100644
--- a/tools/perf/util/evlist.c
+++ b/tools/perf/util/evlist.c
@@ -769,7 +769,7 @@
 
 	evlist->overwrite = overwrite;
 	evlist->mmap_len = perf_evlist__mmap_size(pages);
-	pr_debug("mmap size %luB\n", evlist->mmap_len);
+	pr_debug("mmap size %zuB\n", evlist->mmap_len);
 	mask = evlist->mmap_len - page_size - 1;
 
 	list_for_each_entry(evsel, &evlist->entries, node) {