linux-kernel - Re: [PATCH v6 7/7] perf intel-pt: Add brief documentation for PEBS via Intel PT

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Date:   Tue, 13 Aug 2019 17:05:46 +0300
From:   Alexander Shishkin <alexander.shishkin@...ux.intel.com>
To:     Arnaldo Carvalho de Melo <acme@...hat.com>
Cc:     Peter Zijlstra <a.p.zijlstra@...llo.nl>,
        Ingo Molnar <mingo@...hat.com>, linux-kernel@...r.kernel.org,
        kan.liang@...ux.intel.com, Adrian Hunter <adrian.hunter@...el.com>,
        alexander.shishkin@...ux.intel.com
Subject: Re: [PATCH v6 7/7] perf intel-pt: Add brief documentation for PEBS via Intel PT

Arnaldo Carvalho de Melo <acme@...hat.com> writes:

> Em Tue, Aug 06, 2019 at 11:46:06AM +0300, Alexander Shishkin escreveu:
>> From: Adrian Hunter <adrian.hunter@...el.com>
>> 
>> Document how to select PEBS via Intel PT and how to display synthesized
>> PEBS samples.
>> 
>> Signed-off-by: Adrian Hunter <adrian.hunter@...el.com>
>> Signed-off-by: Alexander Shishkin <alexander.shishkin@...ux.intel.com>
>> ---
>>  tools/perf/Documentation/intel-pt.txt | 15 +++++++++++++++
>>  1 file changed, 15 insertions(+)
>> 
>> diff --git a/tools/perf/Documentation/intel-pt.txt b/tools/perf/Documentation/intel-pt.txt
>> index 50c5b60101bd..8dc513b6607b 100644
>> --- a/tools/perf/Documentation/intel-pt.txt
>> +++ b/tools/perf/Documentation/intel-pt.txt
>> @@ -919,3 +919,18 @@ amended to take the number of elements as a parameter.
>>  
>>  Note there is currently no advantage to using Intel PT instead of LBR, but
>>  that may change in the future if greater use is made of the data.
>> +
>> +
>> +PEBS via Intel PT
>> +=================
>> +
>> +Some hardware has the feature to redirect PEBS records to the Intel PT trace.
>> +Recording is selected by using the aux-output config term e.g.
>> +
>> +	perf record  -c 10000 -e cycles/aux-output/ppp -e intel_pt/branch=0/ uname
>> +
>> +Note that currently, software only supports redirecting at most one PEBS event.
>
> So, with these patches, but not the kernel ones I end up getting:
>
> [root@...co ~]# perf record  -c 10000 -e cycles/aux-output/ppp -e intel_pt/branch=0/ uname

FWIW, the correct command line for that would have the two events
grouped and intel_pt be the group leader.

Regards,
--
Alex