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

From: Jiri Olsa
Date: Mon Aug 11 2014 - 09:12:40 EST


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?

jirka
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