Re: [PATCH v6 07/11] drivers: perf: hisi: Add support for Hisilicon SoC event counters

[Anurup M]

On Thursday 30 March 2017 04:16 PM, Mark Rutland wrote:
> > > > > +	/*
> > > > > > >>>+	 * We must NOT create groups containing mixed PMUs, although
> > > > > > >>>+	 * software events are acceptable
> > > > > > >>>+	 */
> > > > > > >>>+	if (event->group_leader->pmu != event->pmu &&
> > > > > > >>>+	    !is_software_event(event->group_leader))
> > > > > > >>>+		return -EINVAL;
> > > > > > >>>+
> > > > > > >>>+	list_for_each_entry(sibling, &event->group_leader->sibling_list,
> > > > > > >>>+			    group_entry)
> > > > > > >>>+		if (sibling->pmu != event->pmu && !is_software_event(sibling))
> > > > > > >>>+			return -EINVAL;
> > > > >Please also check the number of counters.
> > >
> > >Sorry, I could not follow this comment correctly. Could you please explain ?
> > >I check the available counters and update used mask in pmu_add -->
> > >get_event_index
> What I meant was that here we should ensure that a group does not
> contain more events than can fit into counters.
>
> For example, if the HW had two counters, we should reject any group with
> more than two events. Such groups can never be scheduled, and make no
> sense.

I have referred drivers/bus/arm-cci.c and could find validate_group and 
validate_event functions,
which create a fake_pmu to check the available counters for the events 
in the group.
Is that the same way which is expected here? Please comment.

Thanks,
Anurup

> Thanks,
> Mark.