Re: [PATCH v3] tools/perf/metricgroup: Fix printing event names of metric group with multiple events incase of overlapping events

From: Jiri Olsa
Date: Mon Feb 10 2020 - 07:11:49 EST


On Thu, Feb 06, 2020 at 10:58:12AM -0800, Joe Perches wrote:
> On Thu, 2020-02-06 at 19:45 +0100, Jiri Olsa wrote:
> > On Fri, Jan 31, 2020 at 10:55:22AM +0530, Kajol Jain wrote:
> >
> > SNIP
> >
> > > ev->metric_leader = metric_events[i];
> > > }
> > > + j++;
> > > }
> > > + ev = metric_events[i];
> > > + evlist_used[ev->idx] = true;
> > > }
> > >
> > > return metric_events[0];
> > > @@ -160,6 +161,9 @@ static int metricgroup__setup_events(struct list_head *groups,
> > > int ret = 0;
> > > struct egroup *eg;
> > > struct evsel *evsel;
> > > + bool evlist_used[perf_evlist->core.nr_entries];
> > > +
> > > + memset(evlist_used, 0, perf_evlist->core.nr_entries);
> >
> > I know I posted this in the previous email, but are we sure bool
> > is always 1 byte? would sizeod(evlist_used) be safer?
> >
> > other than that it looks ok
> >
> > Andi, you're ok with this?
>
> stack declarations of variable length arrays are not
> a good thing.
>
> https://lwn.net/Articles/749089/
>
> and
>
> bool evlist_used[perf_evlist->core.nr_entries] = {};

hum, I think we already have few of them in perf ;-)
thanks for the link

right, that initialization is of course much better, thanks

jirka