Re: [PATCH] perf docu: Update section on cpu topology

From: Thomas-Mich Richter
Date: Tue May 29 2018 - 03:44:45 EST


On 05/28/2018 09:54 PM, Arnaldo Carvalho de Melo wrote:
> Em Mon, May 28, 2018 at 09:44:33AM +0200, Thomas Richter escreveu:
>> Add an explanation of each cpu's core and socket
>> identifier to the documentation.
>
> Thanks, applying. I guess it is not that worth to mention that older
> files may have just the string lists, right?
>
> - Arnaldo

Ah, sorry but that did not cross my mind....

It was introduced with commit
2bb00d2f95193 ("perf tools: Store the cpu socket and core ids in the perf.data header")
and is available since Linux 4.4

Hope this helps...

>
>> Signed-off-by: Thomas Richter <tmricht@xxxxxxxxxxxxx>
>> ---
>> tools/perf/Documentation/perf.data-file-format.txt | 8 ++++++++
>> 1 file changed, 8 insertions(+)
>>
>> diff --git a/tools/perf/Documentation/perf.data-file-format.txt b/tools/perf/Documentation/perf.data-file-format.txt
>> index d00f0d51cab8..c57904a526ce 100644
>> --- a/tools/perf/Documentation/perf.data-file-format.txt
>> +++ b/tools/perf/Documentation/perf.data-file-format.txt
>> @@ -153,10 +153,18 @@ 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 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 {
>> struct perf_header_string_list cores; /* Variable length */
>> struct perf_header_string_list threads; /* Variable length */
>> + struct {
>> + uint32_t core_id;
>> + uint32_t socket_id;
>> + } cpus[nr]; /* Variable length records */
>> };
>>
>> Example:
>> --
>> 2.14.3
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Thomas Richter, Dept 3303, IBM s390 Linux Development, Boeblingen, Germany
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