[tip:perf/core] perf.data documentation: Clarify HEADER_SAMPLE_TOPOLOGY format

From: tip-bot for Vince Weaver
Date: Thu Aug 15 2019 - 05:35:34 EST


Commit-ID: 3143906c2770778d89b730e0342b745d1b4a8303
Gitweb: https://git.kernel.org/tip/3143906c2770778d89b730e0342b745d1b4a8303
Author: Vince Weaver <vincent.weaver@xxxxxxxxx>
AuthorDate: Thu, 1 Aug 2019 14:30:43 -0400
Committer: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
CommitDate: Wed, 14 Aug 2019 10:59:59 -0300

perf.data documentation: Clarify HEADER_SAMPLE_TOPOLOGY format

The perf.data file format documentation for HEADER_SAMPLE_TOPOLOGY
specifies the layout in a confusing manner that doesn't match the rest
of the document. This patch attempts to describe things consistent with
the rest of the file.

Signed-off-by: Vince Weaver <vincent.weaver@xxxxxxxxx>
Acked-by: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
Cc: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Cc: Chong Jiang <chongjiang@xxxxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Simon Que <sque@xxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/alpine.DEB.2.21.1908011425240.14303@macbook-air
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
tools/perf/Documentation/perf.data-file-format.txt | 25 +++++++++++++---------
1 file changed, 15 insertions(+), 10 deletions(-)

diff --git a/tools/perf/Documentation/perf.data-file-format.txt b/tools/perf/Documentation/perf.data-file-format.txt
index d030c87ed9f5..b0152e1095c5 100644
--- a/tools/perf/Documentation/perf.data-file-format.txt
+++ b/tools/perf/Documentation/perf.data-file-format.txt
@@ -298,16 +298,21 @@ Physical memory map and its node assignments.

The format of data in MEM_TOPOLOGY is as follows:

- 0 - version | for future changes
- 8 - block_size_bytes | /sys/devices/system/memory/block_size_bytes
- 16 - count | number of nodes
-
-For each node we store map of physical indexes:
-
- 32 - node id | node index
- 40 - size | size of bitmap
- 48 - bitmap | bitmap of memory indexes that belongs to node
- | /sys/devices/system/node/node<NODE>/memory<INDEX>
+ u64 version; // Currently 1
+ u64 block_size_bytes; // /sys/devices/system/memory/block_size_bytes
+ u64 count; // number of nodes
+
+struct memory_node {
+ u64 node_id; // node index
+ u64 size; // size of bitmap
+ struct bitmap {
+ /* size of bitmap again */
+ u64 bitmapsize;
+ /* bitmap of memory indexes that belongs to node */
+ /* /sys/devices/system/node/node<NODE>/memory<INDEX> */
+ u64 entries[(bitmapsize/64)+1];
+ }
+}[count];

The MEM_TOPOLOGY can be displayed with following command: