diff --git a/tools/perf/builtin-diff.c b/tools/perf/builtin-diff.c
index b39f3a1..9a0872f 100644
--- a/tools/perf/builtin-diff.c
+++ b/tools/perf/builtin-diff.c
@@ -30,7 +30,8 @@
 	return -ENOMEM;
 }
 
-static int diff__process_sample_event(union perf_event *event,
+static int diff__process_sample_event(struct perf_event_ops *ops __used,
+				      union perf_event *event,
 				      struct perf_sample *sample,
 				      struct perf_evsel *evsel __used,
 				      struct perf_session *session)