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diff --git a/Documentation/trace/ftrace.txt b/Documentation/trace/ftrace.txt
index d4601df6e72e..54213e5c23f6 100644
--- a/Documentation/trace/ftrace.txt
+++ b/Documentation/trace/ftrace.txt
@@ -539,6 +539,30 @@ of ftrace. Here is a list of some of the key files:
See events.txt for more information.
+ timestamp_mode:
+
+ Certain tracers may change the timestamp mode used when
+ logging trace events into the event buffer. Events with
+ different modes can coexist within a buffer but the mode in
+ effect when an event is logged determines which timestamp mode
+ is used for that event. The default timestamp mode is
+ 'delta'.
+
+ Usual timestamp modes for tracing:
+
+ # cat timestamp_mode
+ [delta] absolute
+
+ The timestamp mode with the square brackets around it is the
+ one in effect.
+
+ delta: Default timestamp mode - timestamp is a delta against
+ a per-buffer timestamp.
+
+ absolute: The timestamp is a full timestamp, not a delta
+ against some other value. As such it takes up more
+ space and is less efficient.
+
hwlat_detector:
Directory for the Hardware Latency Detector.