[tip:perf/core] perf data: Fix perf.data documentation for HEADER_CPU_TOPOLOGY

From: tip-bot for Arnaldo Carvalho de Melo
Date: Mon Jun 17 2019 - 15:41:47 EST


Commit-ID: 36edfb940195b62c79bc8b148720c8275659a8c7
Gitweb: https://git.kernel.org/tip/36edfb940195b62c79bc8b148720c8275659a8c7
Author: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
AuthorDate: Thu, 6 Jun 2019 17:03:18 -0300
Committer: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
CommitDate: Mon, 10 Jun 2019 16:20:11 -0300

perf data: Fix perf.data documentation for HEADER_CPU_TOPOLOGY

The 'die' info isn't in the same array as core and socket ids, and we
missed the 'dies' string list, that comes right after the 'core' +
'socket' id variable length array, followed by the VLA for the dies.

Cc: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Cc: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Kan Liang <kan.liang@xxxxxxxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Fixes: c9cb12c5ba08 ("perf header: Add die information in CPU topology")
Link: https://lkml.kernel.org/n/tip-nubi6mxp2n8ofvlx7ph6k3h6@xxxxxxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
tools/perf/Documentation/perf.data-file-format.txt | 29 ++++++++++++++++------
1 file changed, 22 insertions(+), 7 deletions(-)

diff --git a/tools/perf/Documentation/perf.data-file-format.txt b/tools/perf/Documentation/perf.data-file-format.txt
index de78183f6881..5f54feb19977 100644
--- a/tools/perf/Documentation/perf.data-file-format.txt
+++ b/tools/perf/Documentation/perf.data-file-format.txt
@@ -151,20 +151,35 @@ struct {

HEADER_CPU_TOPOLOGY = 13,

-String lists defining the core and CPU threads topology.
-The string lists are followed by a variable length array
-which contains core_id, die_id (for x86) and socket_id of each cpu.
-The number of entries can be determined by the size of the
-section minus the sizes of both string lists.
-
struct {
+ /*
+ * First revision of HEADER_CPU_TOPOLOGY
+ *
+ * See 'struct perf_header_string_list' definition earlier
+ * in this file.
+ */
+
struct perf_header_string_list cores; /* Variable length */
struct perf_header_string_list threads; /* Variable length */
+
+ /*
+ * Second revision of HEADER_CPU_TOPOLOGY, older tools
+ * will not consider what comes next
+ */
+
struct {
uint32_t core_id;
- uint32_t die_id;
uint32_t socket_id;
} cpus[nr]; /* Variable length records */
+ /* 'nr' comes from previously processed HEADER_NRCPUS's nr_cpu_avail */
+
+ /*
+ * Third revision of HEADER_CPU_TOPOLOGY, older tools
+ * will not consider what comes next
+ */
+
+ struct perf_header_string_list dies; /* Variable length */
+ uint32_t die_id[nr_cpus_avail]; /* from previously processed HEADER_NR_CPUS, VLA */
};

Example: