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Subject[patch 04/10] perf_event_open.2: 4.1 data_offset and data_size fields

This manpage patch relates to the addition of the data_offset
and data_size fields to the perf_event mmap buffer, as added
in the following commit:

commit e8c6deac69629c0cb97c3d3272f8631ef17f8f0f
Author: Alexander Shishkin <>

perf: Add data_{offset,size} to user_page

Signed-off-by: Alexander Shishkin <>
Signed-off-by: Peter Zijlstra (Intel) <>
Cc: Borislav Petkov <>
Cc: Frederic Weisbecker <>
Cc: H. Peter Anvin <>
Cc: Kaixu Xia <>
Cc: Linus Torvalds <>
Cc: Mike Galbraith <>
Cc: Paul Mackerras <>
Cc: Robert Richter <>
Cc: Stephane Eranian <>
Cc: Thomas Gleixner <>
Signed-off-by: Ingo Molnar <>

Signed-off-by: Vince Weaver <>

diff --git a/man2/perf_event_open.2 b/man2/perf_event_open.2
index 01ee579..8bd37da 100644
--- a/man2/perf_event_open.2
+++ b/man2/perf_event_open.2
@@ -1348,6 +1348,9 @@ struct perf_event_mmap_page {
__u64 __reserved[120]; /* Pad to 1k */
__u64 data_head; /* head in the data section */
__u64 data_tail; /* user-space written tail */
+ __u64 data_offset; /* where the buffer starts */
+ __u64 data_size; /* data buffer size */
@@ -1564,6 +1567,16 @@ the
.I data_tail
value should be written by user space to reflect the last read data.
In this case, the kernel will not overwrite unread data.
+.IR data_offset " (since Linux 4.1)"
+.\" commit e8c6deac69629c0cb97c3d3272f8631ef17f8f0f
+Contains the offset of the location in the mmap buffer
+where perf sample data begins.
+.IR data_size " (since Linux 4.1)"
+.\" commit e8c6deac69629c0cb97c3d3272f8631ef17f8f0f
+Contains the size of the perf sample region within
+the mmap buffer.
The following 2^n ring-buffer pages have the layout described below.

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