This manpage patch relates to the addition of the AUX sample flag
AUX_FLAG_OVERWRITE as added in the following commit:
commit 2023a0d2829e521fe6ad6b9907f3f90bfbf57142
Author: Alexander Shishkin <[email protected]>
perf: Support overwrite mode for the AUX area
Signed-off-by: Alexander Shishkin <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Frederic Weisbecker <[email protected]>
Cc: H. Peter Anvin <[email protected]>
Cc: Kaixu Xia <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Mike Galbraith <[email protected]>
Cc: Paul Mackerras <[email protected]>
Cc: Robert Richter <[email protected]>
Cc: Stephane Eranian <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Link:
http://lkml.kernel.org/r/1421237903-181015-9-git-send-email-alexander.shish...@linux.intel.com
Signed-off-by: Ingo Molnar <[email protected]>
Signed-off-by: Vince Weaver <[email protected]>
diff --git a/man2/perf_event_open.2 b/man2/perf_event_open.2
index dfb0b64..238eb62 100644
--- a/man2/perf_event_open.2
+++ b/man2/perf_event_open.2
@@ -1670,6 +1670,15 @@ rlimit as well as the
.I perf_event_mlock_kb
allowance.
+By default the AUX buffer will be truncated if it will not fit
+in the available space in the ring buffer.
+If the AUX buffer is mapped as a read only buffer, then it will
+operate in ring buffer mode where old data will be overwritten
+by new.
+In overwrite mode it might not be possible to infer where the
+new data began, and it is the consumer's job to disable
+measurement while reading to avoid possible data races.
+
The
.IR aux_head " and " aux_tail
ring buffer pointers have the same behavior and ordering
@@ -2476,6 +2485,10 @@ describes the aux update.
.B PERF_AUX_FLAG_TRUNCATED
if set then the data returned was truncated to fit the available
buffer size.
+.TP
+.B PERF_AUX_FLAG_OVERWRITE
+.\" commit 2023a0d2829e521fe6ad6b9907f3f90bfbf57142
+if set then the data returned has overwritten previous data.
.RE
.RE
.RE
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
