Re: [PATCH v5 4/5] perf stat: Save aggr value to first member of prev_raw_counts

[Jin, Yao]

On 5/18/2020 8:48 PM, Jiri Olsa wrote:
> On Thu, May 14, 2020 at 01:36:37PM +0800, Jin Yao wrote:
> > To collect the overall statistics for interval mode, we copy the
> > counts from evsel->prev_raw_counts to evsel->counts.
> >
> > For AGGR_GLOBAL mode, because the perf_stat_process_counter creates
> > aggr values from per cpu values, but the per cpu values are 0,
> > so the calculated aggr values will be always 0.
> >
> > This patch uses a trick that saves the previous aggr value to
> > the first member of perf_counts, then aggr calculation in
> > process_counter_values can work correctly for AGGR_GLOBAL.
> >
> > Signed-off-by: Jin Yao <yao.jin@xxxxxxxxxxxxxxx>
> > ---
> >   tools/perf/util/stat.c | 10 ++++++++++
> >   tools/perf/util/stat.h |  1 +
> >   2 files changed, 11 insertions(+)
> >
> > diff --git a/tools/perf/util/stat.c b/tools/perf/util/stat.c
> > index aadc723ce871..fbabdd5b9b62 100644
> > --- a/tools/perf/util/stat.c
> > +++ b/tools/perf/util/stat.c
> > @@ -249,6 +249,16 @@ void perf_evlist__copy_prev_raw_counts(struct evlist *evlist)
> >   		perf_evsel__copy_prev_raw_counts(evsel);
> >   }
> >   
>
> much better, please put some comments in here explaning wha
> is this for, because it's not obvious ;-)
>
> thanks,
> jirka

Thanks, I will put some comments in v6.

Thanks
Jin Yao

> > +void perf_evlist__save_aggr_prev_raw_counts(struct evlist *evlist)
> > +{
> > +	struct evsel *evsel;
> > +
> > +	evlist__for_each_entry(evlist, evsel) {
> > +		*perf_counts(evsel->prev_raw_counts, 0, 0) =
> > +			evsel->prev_raw_counts->aggr;
> > +	}
> > +}
> > +
> >   static void zero_per_pkg(struct evsel *counter)
> >   {
> >   	if (counter->per_pkg_mask)
> > diff --git a/tools/perf/util/stat.h b/tools/perf/util/stat.h
> > index 62cf72c71869..18ead55756cc 100644
> > --- a/tools/perf/util/stat.h
> > +++ b/tools/perf/util/stat.h
> > @@ -199,6 +199,7 @@ void perf_evlist__free_stats(struct evlist *evlist);
> >   void perf_evlist__reset_stats(struct evlist *evlist);
> >   void perf_evlist__reset_prev_raw_counts(struct evlist *evlist);
> >   void perf_evlist__copy_prev_raw_counts(struct evlist *evlist);
> > +void perf_evlist__save_aggr_prev_raw_counts(struct evlist *evlist);
> >   
> >   int perf_stat_process_counter(struct perf_stat_config *config,
> >   			      struct evsel *counter);
> > --
> > 2.17.1