Re: [PATCH 1/1] perf,tools: open event on evsel cpus and threads

From: Arnaldo Carvalho de Melo
Date: Mon Aug 31 2015 - 17:34:42 EST


Em Mon, Aug 31, 2015 at 09:28:43PM +0000, Liang, Kan escreveu:
>
>
>
> >
> > Em Mon, Aug 31, 2015 at 09:06:29PM +0000, Liang, Kan escreveu:
> > >
> > >
> > > > Em Fri, Aug 21, 2015 at 03:54:36PM +0200, Jiri Olsa escreveu:
> > > > > On Fri, Aug 21, 2015 at 02:23:14AM -0400, kan.liang@xxxxxxxxx wrote:
> > > > > > From: Kan Liang <kan.liang@xxxxxxxxx>
> > > > > >
> > > > > > evsel may have different cpus and threads as evlist's.
> > > > > > Use it's own cpus and threads, when open evsel in perf record.
> > > > >
> > > > > Acked-by: Jiri Olsa <jolsa@xxxxxxxxxx>
> > > >
> > > > Applying, I wonder if this isn't affecting other tools as well...
> > > > And also
> > >
> > > No, it doesn't affect other tools.
> > >
> > > > perf_evlist__open(), that has to be fixed as well, right?
> > > >
> > >
> > > Umm... Right.
> > > We should fix it in perf_evlist__open as well.
> > > IIRC, Jirka once planned to send out a cleanup patch separately for
> > > this kind of issue (perf_evsel__enable also need to be fixed) on other
> > > tools.
> >
> > So now that we have a backpointer, perhaps we should have a:
> >
> > struct thread_map *perf_evsel__threads(struct perf_evsel *evsel) {
> > return evsel->threads ?: evsel->evlist ? evsel->evlist->threads :
> > NULL; }
> >
> > Ditto for cpus and then change all occurrences of evsel->threads with
> > perf_evsel__threads(), right?
>
> No. We need to change all evlist->threads with evsel->threads.
> Ditto for cpus.
> The event should use its own thread/cpu list.

Which is equivalent, but IIRC doing it the way you do is better because
we do that forwarding already, right?

Lemme check... Yeah, it is done in perf_evlist__propagate_maps(), so, as
long as that function was called, we can access evsel->{threads,cpus}
and it will use evlist->{threads,cpus} if those entries were not set
before perf_evlist__propagate_maps() was called.

- Arnaldo

> > > Thanks,
> > > Kan
> > >
> > > > - Arnaldo
> > > >
> > > > > thanks,
> > > > > jirka
> > > > >
> > > > > >
> > > > > > Signed-off-by: Kan Liang <kan.liang@xxxxxxxxx>
> > > > > > ---
> > > > > > tools/perf/builtin-record.c | 2 +-
> > > > > > tools/perf/util/evlist.c | 4 ++++
> > > > > > 2 files changed, 5 insertions(+), 1 deletion(-)
> > > > > >
> > > > > > diff --git a/tools/perf/builtin-record.c
> > > > > > b/tools/perf/builtin-record.c index 25cf6b4..a0178bf 100644
> > > > > > --- a/tools/perf/builtin-record.c
> > > > > > +++ b/tools/perf/builtin-record.c
> > > > > > @@ -279,7 +279,7 @@ static int record__open(struct record *rec)
> > > > > >
> > > > > > evlist__for_each(evlist, pos) {
> > > > > > try_again:
> > > > > > - if (perf_evsel__open(pos, evlist->cpus, evlist-
> > >threads) <
> > > > 0) {
> > > > > > + if (perf_evsel__open(pos, pos->cpus, pos-
> > >threads) < 0) {
> > > > > > if (perf_evsel__fallback(pos, errno, msg,
> > > > sizeof(msg))) {
> > > > > > if (verbose)
> > > > > > ui__warning("%s\n", msg);
> > > > > > diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
> > > > > > index 373f65b..be6fde9 100644
> > > > > > --- a/tools/perf/util/evlist.c
> > > > > > +++ b/tools/perf/util/evlist.c
> > > > > > @@ -1179,6 +1179,10 @@ int perf_evlist__apply_filters(struct
> > > > perf_evlist *evlist, struct perf_evsel **e
> > > > > > if (evsel->filter == NULL)
> > > > > > continue;
> > > > > >
> > > > > > + /*
> > > > > > + * filters only work for tracepoint event, which
> > doesn't
> > > > have cpu limit.
> > > > > > + * So evlist and evsel should always be same.
> > > > > > + */
> > > > > > err = perf_evsel__apply_filter(evsel, ncpus,
> > nthreads,
> > > > evsel->filter);
> > > > > > if (err) {
> > > > > > *err_evsel = evsel;
> > > > > > --
> > > > > > 1.8.3.1
> > > > > >
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