diff --git a/[refs] b/[refs]
index f26bfb3860ec..765d43db1406 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 66e274f3b8d7fc89d38997e85b900e188f8d5cc0
+refs/heads/master: 18408ddc01136f505ae357c03f0d8e50b10e0db6
diff --git a/trunk/tools/perf/util/event.h b/trunk/tools/perf/util/event.h
index d26dc887ce52..fa7c50b654e1 100644
--- a/trunk/tools/perf/util/event.h
+++ b/trunk/tools/perf/util/event.h
@@ -4,6 +4,9 @@
 #include "util.h"
 #include <linux/list.h>
 
+/*
+ * PERF_SAMPLE_IP | PERF_SAMPLE_TID | *
+ */
 struct ip_event {
 	struct perf_event_header header;
 	u64 ip;
@@ -38,6 +41,9 @@ struct lost_event {
 	u64 lost;
 };
 
+/*
+ * PERF_FORMAT_ENABLED | PERF_FORMAT_RUNNING | PERF_FORMAT_ID
+ */
 struct read_event {
 	struct perf_event_header header;
 	u32 pid,tid;