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Subject[PATCH 5/5] perf record: Describe perf.data directory format
Date
Adding perf.data-directory-format.txt to describe the
directory data layout.

Link: http://lkml.kernel.org/n/tip-1c8u1thx63v2ldwfdas4xc5d@git.kernel.org
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
.../perf.data-directory-format.txt | 54 +++++++++++++++++++
1 file changed, 54 insertions(+)
create mode 100644 tools/perf/Documentation/perf.data-directory-format.txt

diff --git a/tools/perf/Documentation/perf.data-directory-format.txt b/tools/perf/Documentation/perf.data-directory-format.txt
new file mode 100644
index 000000000000..bbd6d31b10c8
--- /dev/null
+++ b/tools/perf/Documentation/perf.data-directory-format.txt
@@ -0,0 +1,54 @@
+perf.data directory format
+
+DISCLAIMER This is not ABI yet and is subject to possible change
+ in following versions of perf. We will remove this
+ disclaimer once the directory format soaks in.
+
+
+This document describes the on-disk perf.data format, generated
+by perf record with --dir option and consumed by the other perf
+tools.
+
+The directory perf.data is created by perf record command by
+using the --dir option:
+
+ $ perf record --dir perf bench sched messaging
+ $ ls -l perf.data
+ total 344
+ -rw-------. 1 jolsa jolsa 43864 Jan 20 22:26 data.0
+ -rw-------. 1 jolsa jolsa 30464 Jan 20 22:26 data.1
+ -rw-------. 1 jolsa jolsa 53816 Jan 20 22:26 data.2
+ -rw-------. 1 jolsa jolsa 30368 Jan 20 22:26 data.3
+ -rw-------. 1 jolsa jolsa 40088 Jan 20 22:26 data.4
+ -rw-------. 1 jolsa jolsa 42592 Jan 20 22:26 data.5
+ -rw-------. 1 jolsa jolsa 56136 Jan 20 22:26 data.6
+ -rw-------. 1 jolsa jolsa 25992 Jan 20 22:26 data.7
+ -rw-------. 1 jolsa jolsa 8832 Jan 20 22:26 header
+
+The header file keeps the standard perf.data file header,
+and the data.* files keep data.
+
+header file
+-----------
+The header file following the standard format describe in
+Documentation/perf.data-file-format doc. Including its data
+portion that is used to store manually synthesized events.
+
+data file
+---------
+The data files layout is described by HEADER_DIR_FORMAT feature.
+Currently it holds only version number (1):
+
+ HEADER_DIR_FORMAT = 24
+
+ struct {
+ uint64_t version;
+ }
+
+The current only only version value 1 means that data files:
+ - follow the 'data.*' format
+ - contain raw events data in standard perf format as read
+ from kernel (and need to be sorted)
+
+Future versions are expected to describe different data files
+layout according to special needs.
--
2.17.2
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