Re: [PATCH 34/41] perf evlist: Add 'system_wide' option

[Adrian Hunter]

On 08/11/2014 04:12 PM, Jiri Olsa wrote:
> On Mon, Jul 14, 2014 at 01:02:58PM +0300, Adrian Hunter wrote:
>> Add an option to cause a selected event
>> to be opened always without a pid when
>> configured by perf_evsel__config().
>>
>> This is needed when using the sched_switch
>> tracepoint to follow object code execution.
>> sched_switch occurs before the task
>> switch and so it cannot record it in a
>> context limited to that task.  Note
>> that also means that sched_switch is
>> useless when capturing data per-thread,
>> as is the 'context-switches' software
>> event for the same reason.
>>
>> Signed-off-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>
>> ---
>>  tools/perf/util/evlist.c | 45 +++++++++++++++++++++++++++++++++++++--------
>>  tools/perf/util/evsel.c  | 31 ++++++++++++++++++++++++++-----
>>  tools/perf/util/evsel.h  |  1 +
>>  3 files changed, 64 insertions(+), 13 deletions(-)
>>
>> diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
>> index 282e83e..c295b7b 100644
>> --- a/tools/perf/util/evlist.c
>> +++ b/tools/perf/util/evlist.c
>> @@ -265,17 +265,27 @@ int perf_evlist__add_newtp(struct perf_evlist *evlist,
>>  	return 0;
>>  }
>>  
>> +static int perf_evlist__nr_threads(struct perf_evlist *evlist,
>> +				   struct perf_evsel *evsel)
>> +{
>> +	if (evsel->system_wide)
>> +		return 1;
>> +	else
>> +		return thread_map__nr(evlist->threads);
>> +}
> 
> how is 'evsel->system_wide' set?

Intel PT sets it for the sched_switch event.


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