diff --git a/include/uapi/linux/perf_event.h b/include/uapi/linux/perf_event.h
index 022d0acf7df0..2881145cda86 100644
--- a/include/uapi/linux/perf_event.h
+++ b/include/uapi/linux/perf_event.h
@@ -951,6 +951,7 @@ union perf_mem_data_src {
  *
  *     in_tx: running in a hardware transaction
  *     abort: aborting a hardware transaction
+ *    cycles: cycles from last branch (or 0 if not supported)
  */
 struct perf_branch_entry {
 	__u64	from;
@@ -959,7 +960,8 @@ struct perf_branch_entry {
 		predicted:1,/* target predicted */
 		in_tx:1,    /* in transaction */
 		abort:1,    /* transaction abort */
-		reserved:60;
+		cycles:16,  /* cycle count to last branch */
+		reserved:44;
 };
 
 #endif /* _UAPI_LINUX_PERF_EVENT_H */