RE: [PATCH V2 1/1] perf/core: don't find side-band event from all pmus

From: Liang, Kan
Date: Thu Mar 31 2016 - 10:06:10 EST




> > +static void perf_event_sb_mask(unsigned int sb_mask,
> > + perf_event_aux_output_cb output,
> > + void *data)
> > +{
> > + int sb;
> > +
> > + for (sb = 0; sb < sb_nr; sb++) {
> > + if (!(sb_mask & (1 << sb)))
> > + continue;
> > + perf_event_sb_iterate(sb, output, data);
> > + }
> > +}
>
> > @@ -5852,7 +5910,8 @@ static void perf_event_task(struct task_struct
> > *task,
> >
> > perf_event_aux(perf_event_task_output,
> > &task_event,
> > - task_ctx);
> > + task_ctx,
> > + (1 << sb_task) | (1 << sb_mmap) | (1 << sb_comm));
> > }
>
> So one side-effect of this change is that the above event can be delivered
> 3 times if you're 'lucky'.
>
> Acme; does userspace care?

Hi Arnaldo,

Do you think if it's an issue for userspace?

Thanks,
Kan