Re: [PATCH v2 16/27] perf evlist: Warn as events from different hybrid PMUs in a group

[Jin, Yao]

Hi Jiri,

On 3/16/2021 7:03 AM, Jiri Olsa wrote:
> On Thu, Mar 11, 2021 at 03:07:31PM +0800, Jin Yao wrote:
>
> SNIP
>
> >   				goto try_again;
> >   			}
> > +
> > +			if (errno == EINVAL && perf_pmu__hybrid_exist())
> > +				evlist__warn_hybrid_group(evlist);
> >   			rc = -errno;
> >   			evsel__open_strerror(pos, &opts->target, errno, msg, sizeof(msg));
> >   			ui__error("%s\n", msg);
> > diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
> > index 7a732508b2b4..6f780a039db0 100644
> > --- a/tools/perf/builtin-stat.c
> > +++ b/tools/perf/builtin-stat.c
> > @@ -239,6 +239,9 @@ static void evlist__check_cpu_maps(struct evlist *evlist)
> >   	struct evsel *evsel, *pos, *leader;
> >   	char buf[1024];
> >   
> > +	if (evlist__hybrid_exist(evlist))
> > +		return;
>
> this should be in separate patch and explained

Now I have another idea. If a group consists of atom events and core events, we still follow current 
disabling group solution?

I mean removing following code:

if (evlist__hybrid_exist(evlist))
	return;

evlist__check_cpu_maps then continues running and disabling the group. But also report with a 
warning that says "WARNING: Group has events from different hybrid PMUs".

Do you like this way?

> > +
> >   	evlist__for_each_entry(evlist, evsel) {
> >   		leader = evsel->leader;
> >   
> > @@ -726,6 +729,10 @@ enum counter_recovery {
> >   static enum counter_recovery stat_handle_error(struct evsel *counter)
> >   {
> >   	char msg[BUFSIZ];
> > +
> > +	if (perf_pmu__hybrid_exist() && errno == EINVAL)
> > +		evlist__warn_hybrid_group(evsel_list);
> > +
> >   	/*
> >   	 * PPC returns ENXIO for HW counters until 2.6.37
> >   	 * (behavior changed with commit b0a873e).
> > diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
> > index f139151b9433..5ec891418cdd 100644
> > --- a/tools/perf/util/evlist.c
> > +++ b/tools/perf/util/evlist.c
> > @@ -2224,3 +2224,47 @@ void evlist__invalidate_all_cpus(struct evlist *evlist)
> >   	perf_cpu_map__put(evlist->core.all_cpus);
> >   	evlist->core.all_cpus = perf_cpu_map__empty_new(1);
> >   }
> > +
> > +static bool group_hybrid_conflict(struct evsel *leader)
> > +{
> > +	struct evsel *pos, *prev = NULL;
> > +
> > +	for_each_group_evsel(pos, leader) {
> > +		if (!pos->pmu_name || !perf_pmu__is_hybrid(pos->pmu_name))
> > +			continue;
> > +
> > +		if (prev && strcmp(prev->pmu_name, pos->pmu_name))
> > +			return true;
> > +
> > +		prev = pos;
> > +	}
> > +
> > +	return false;
> > +}
> > +
> > +void evlist__warn_hybrid_group(struct evlist *evlist)
> > +{
> > +	struct evsel *evsel;
> > +
> > +	evlist__for_each_entry(evlist, evsel) {
> > +		if (evsel__is_group_leader(evsel) &&
> > +		    evsel->core.nr_members > 1 &&
>
> hm, could we just iterate all the members and make sure the first found
> hybrid event's pmu matches the pmu of the rest hybrid events in the list?

'{cpu_core/event1/,cpu_core/event2/}','{cpu_atom/event3/,cpu_atom/event4/}'

Two or more groups need to be supported. We get the first hybrid event's pmu (cpu_core in this 
example) but it doesn't match the cpu_atom/event3/ and cpu_atom/event4/. But actually this case 
should be supported, right?

> > +		    group_hybrid_conflict(evsel)) {
> > +			WARN_ONCE(1, "WARNING: Group has events from "
> > +				     "different hybrid PMUs\n");
> > +			return;
> > +		}
> > +	}
> > +}
> > +
> > +bool evlist__hybrid_exist(struct evlist *evlist)
>
> evlist__has_hybrid seems better

Yes, agree.

Thanks
Jin Yao

> jirka