Messages in this thread | | | Date | Sun, 23 Sep 2018 23:44:26 +0200 | From | Jiri Olsa <> | Subject | Re: [PATCH v2 1/1] perf: Sharing PMU counters across compatible events |
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On Tue, Sep 11, 2018 at 01:29:32PM +0000, Song Liu wrote:
SNIP
> >>> > >>> jirka > >> > >> I am not sure I am following. The pmu is disabled when we call > >> event_pmu_add(). Why do we need to read before calling pmu->add()? > >> And this is the first added dup event for this master, so we don't > >> need to worry about others. > >> > >> Does this make sense? > > > > I was just thinking since the pmu is disable we could > > we don't need to read the event on 2 places.. it's almost > > identic code > > How about something like: > > > +/* PMU sharing aware version of event->pmu->add() */ > +static int event_pmu_add(struct perf_event *event, > + struct perf_event_context *ctx) > +{ > + struct perf_event_dup *dup; > + int ret; > + > + /* no sharing, just do event->pmu->add() */ > + if (event->dup_id == -1) > + return event->pmu->add(event, PERF_EF_START); > + > + dup = &ctx->dup_events[event->dup_id]; > + > + if (dup->active_event_count = 0) { > + /* try add master */ > + ret = event->pmu->add(dup->master, PERF_EF_START); > + if (ret) > + return ret; > + } > + > + dup->active_event_count++; > + event->pmu->read(dup->master); > + event->dup_base_count = dup_read_count(dup); > + event->dup_base_child_count = dup_read_child_count(dup); > + > + return 0; > +}
yep, seems ok
jirka
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