Re: [PATCH V6 09/14] perf/x86/intel: Support TopDown metrics on Ice Lake

[Liang, Kan]

On 7/21/2020 10:31 AM, peterz@xxxxxxxxxxxxx wrote:
> On Tue, Jul 21, 2020 at 10:23:36AM -0400, Liang, Kan wrote:
>
> > Patch 13 forces the slots event to be part of a metric group. In patch 7,
> > for a metric group, we only update the values once with slots event.
> > I think the normal case mentioned above should not happen.
> >
> > +	/* Only need to call update_topdown_event() once for group read. */
> > +	if ((cpuc->txn_flags & PERF_PMU_TXN_READ) &&
> > +	    !is_slots_event(event))
> > +		return;
> > +
> > +	perf_pmu_disable(event->pmu);
> > +	x86_pmu.update_topdown_event(event);
> > +	perf_pmu_enable(event->pmu);
>
> Ah, I missed that.
>
> That also requires SLOTS to be the leader so that it will be the first
> read. Did we enforce that somewhere?

I think it's missed in the current patch set. The suggested code in 
patch 11 forces SLOTS to be the leader. I will apply it in V7.

Thanks,
Kan