1 files changed, 11 insertions, 1 deletions

diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index b9950b1620d8..2814ead4adb8 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -215,8 +215,9 @@ struct perf_event_attr {
                                  */
                                 precise_ip     :  2, /* skid constraint       */
                                 mmap_data      :  1, /* non-exec mmap data    */
+                                sample_id_all  :  1, /* sample_type all events */
 
-                                __reserved_1   : 46;
+                                __reserved_1   : 45;
 
         union {
                 __u32           wakeup_events;    /* wakeup every n events */
@@ -327,6 +328,15 @@ struct perf_event_header {
 enum perf_event_type {
 
         /*
+         * If perf_event_attr.sample_id_all is set then all event types will
+         * have the sample_type selected fields related to where/when
+         * (identity) an event took place (TID, TIME, ID, CPU, STREAM_ID)
+         * described in PERF_RECORD_SAMPLE below, it will be stashed just after
+         * the perf_event_header and the fields already present for the existing
+         * fields, i.e. at the end of the payload. That way a newer perf.data
+         * file will be supported by older perf tools, with these new optional
+         * fields being ignored.
+         *
          * The MMAP events record the PROT_EXEC mappings so that we can
          * correlate userspace IPs to code. They have the following structure:
          *