[2/2] perf stat: Show average value on multiple runs

  When -r option is used, perf stat runs the command multiple times and
update stats in the evsel->stats.res_stats for global aggregation.  But
the value is never used and the value it prints at the end is just the
value from the last run.  I think we should print the average number of
multiple runs.

Add evlist__copy_res_stats() to update the aggr counter (for display)
using the values in the evsel->stats.res_stats.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
---
 tools/perf/builtin-stat.c |  5 ++++-
 tools/perf/util/stat.c    | 22 ++++++++++++++++++++++
 tools/perf/util/stat.h    |  1 +
 3 files changed, 27 insertions(+), 1 deletion(-)
  

On Fri, Jun 16, 2023 at 12:32:11AM -0700, Namhyung Kim wrote:
> When -r option is used, perf stat runs the command multiple times and
> update stats in the evsel->stats.res_stats for global aggregation.  But
> the value is never used and the value it prints at the end is just the
> value from the last run.  I think we should print the average number of
> multiple runs.
> 
> Add evlist__copy_res_stats() to update the aggr counter (for display)
> using the values in the evsel->stats.res_stats.
> 
> Signed-off-by: Namhyung Kim <namhyung@kernel.org>

this is the 'real' fix right? I thought this was the way it worked before

anyway works nicely now, would be nice to add some tests for this,
but not sure how bad it'd be ;-)

Acked/Tested-by: Jiri Olsa <jolsa@kernel.org>

thanks,
jirka

> ---
>  tools/perf/builtin-stat.c |  5 ++++-
>  tools/perf/util/stat.c    | 22 ++++++++++++++++++++++
>  tools/perf/util/stat.h    |  1 +
>  3 files changed, 27 insertions(+), 1 deletion(-)
> 
> diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
> index e549862f90f0..42f84975a4d5 100644
> --- a/tools/perf/builtin-stat.c
> +++ b/tools/perf/builtin-stat.c
> @@ -2829,8 +2829,11 @@ int cmd_stat(int argc, const char **argv)
>  		}
>  	}
>  
> -	if (!forever && status != -1 && (!interval || stat_config.summary))
> +	if (!forever && status != -1 && (!interval || stat_config.summary)) {
> +		if (stat_config.run_count > 1)
> +			evlist__copy_res_stats(&stat_config, evsel_list);
>  		print_counters(NULL, argc, argv);
> +	}
>  
>  	evlist__finalize_ctlfd(evsel_list);
>  
> diff --git a/tools/perf/util/stat.c b/tools/perf/util/stat.c
> index 0f7b8a8cdea6..967e583392c7 100644
> --- a/tools/perf/util/stat.c
> +++ b/tools/perf/util/stat.c
> @@ -264,6 +264,28 @@ void evlist__copy_prev_raw_counts(struct evlist *evlist)
>  		evsel__copy_prev_raw_counts(evsel);
>  }
>  
> +static void evsel__copy_res_stats(struct evsel *evsel)
> +{
> +	struct perf_stat_evsel *ps = evsel->stats;
> +
> +	/*
> +	 * For GLOBAL aggregation mode, it updates the counts for each run
> +	 * in the evsel->stats.res_stats.  See perf_stat_process_counter().
> +	 */
> +	*ps->aggr[0].counts.values = avg_stats(&ps->res_stats);
> +}
> +
> +void evlist__copy_res_stats(struct perf_stat_config *config, struct evlist *evlist)
> +{
> +	struct evsel *evsel;
> +
> +	if (config->aggr_mode != AGGR_GLOBAL)
> +		return;
> +
> +	evlist__for_each_entry(evlist, evsel)
> +		evsel__copy_res_stats(evsel);
> +}
> +
>  static size_t pkg_id_hash(long __key, void *ctx __maybe_unused)
>  {
>  	uint64_t *key = (uint64_t *) __key;
> diff --git a/tools/perf/util/stat.h b/tools/perf/util/stat.h
> index 7abff7cbb5a1..1cbc26b587ba 100644
> --- a/tools/perf/util/stat.h
> +++ b/tools/perf/util/stat.h
> @@ -182,6 +182,7 @@ void evlist__save_aggr_prev_raw_counts(struct evlist *evlist);
>  
>  int evlist__alloc_aggr_stats(struct evlist *evlist, int nr_aggr);
>  void evlist__reset_aggr_stats(struct evlist *evlist);
> +void evlist__copy_res_stats(struct perf_stat_config *config, struct evlist *evlist);
>  
>  int perf_stat_process_counter(struct perf_stat_config *config,
>  			      struct evsel *counter);
> -- 
> 2.41.0.162.gfafddb0af9-goog
>
  

On Sat, Jun 17, 2023 at 11:45 AM Jiri Olsa <olsajiri@gmail.com> wrote:
>
> On Fri, Jun 16, 2023 at 12:32:11AM -0700, Namhyung Kim wrote:
> > When -r option is used, perf stat runs the command multiple times and
> > update stats in the evsel->stats.res_stats for global aggregation.  But
> > the value is never used and the value it prints at the end is just the
> > value from the last run.  I think we should print the average number of
> > multiple runs.
> >
> > Add evlist__copy_res_stats() to update the aggr counter (for display)
> > using the values in the evsel->stats.res_stats.
> >
> > Signed-off-by: Namhyung Kim <namhyung@kernel.org>
>
> this is the 'real' fix right? I thought this was the way it worked before

It worked like the patch 1/2 before.

>
> anyway works nicely now, would be nice to add some tests for this,
> but not sure how bad it'd be ;-)

Maybe we can parse the raw counter output from the -v option and
calculate the average then compare.

>
> Acked/Tested-by: Jiri Olsa <jolsa@kernel.org>

Thanks,
Namhyung


>
> > ---
> >  tools/perf/builtin-stat.c |  5 ++++-
> >  tools/perf/util/stat.c    | 22 ++++++++++++++++++++++
> >  tools/perf/util/stat.h    |  1 +
> >  3 files changed, 27 insertions(+), 1 deletion(-)
> >
> > diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
> > index e549862f90f0..42f84975a4d5 100644
> > --- a/tools/perf/builtin-stat.c
> > +++ b/tools/perf/builtin-stat.c
> > @@ -2829,8 +2829,11 @@ int cmd_stat(int argc, const char **argv)
> >               }
> >       }
> >
> > -     if (!forever && status != -1 && (!interval || stat_config.summary))
> > +     if (!forever && status != -1 && (!interval || stat_config.summary)) {
> > +             if (stat_config.run_count > 1)
> > +                     evlist__copy_res_stats(&stat_config, evsel_list);
> >               print_counters(NULL, argc, argv);
> > +     }
> >
> >       evlist__finalize_ctlfd(evsel_list);
> >
> > diff --git a/tools/perf/util/stat.c b/tools/perf/util/stat.c
> > index 0f7b8a8cdea6..967e583392c7 100644
> > --- a/tools/perf/util/stat.c
> > +++ b/tools/perf/util/stat.c
> > @@ -264,6 +264,28 @@ void evlist__copy_prev_raw_counts(struct evlist *evlist)
> >               evsel__copy_prev_raw_counts(evsel);
> >  }
> >
> > +static void evsel__copy_res_stats(struct evsel *evsel)
> > +{
> > +     struct perf_stat_evsel *ps = evsel->stats;
> > +
> > +     /*
> > +      * For GLOBAL aggregation mode, it updates the counts for each run
> > +      * in the evsel->stats.res_stats.  See perf_stat_process_counter().
> > +      */
> > +     *ps->aggr[0].counts.values = avg_stats(&ps->res_stats);
> > +}
> > +
> > +void evlist__copy_res_stats(struct perf_stat_config *config, struct evlist *evlist)
> > +{
> > +     struct evsel *evsel;
> > +
> > +     if (config->aggr_mode != AGGR_GLOBAL)
> > +             return;
> > +
> > +     evlist__for_each_entry(evlist, evsel)
> > +             evsel__copy_res_stats(evsel);
> > +}
> > +
> >  static size_t pkg_id_hash(long __key, void *ctx __maybe_unused)
> >  {
> >       uint64_t *key = (uint64_t *) __key;
> > diff --git a/tools/perf/util/stat.h b/tools/perf/util/stat.h
> > index 7abff7cbb5a1..1cbc26b587ba 100644
> > --- a/tools/perf/util/stat.h
> > +++ b/tools/perf/util/stat.h
> > @@ -182,6 +182,7 @@ void evlist__save_aggr_prev_raw_counts(struct evlist *evlist);
> >
> >  int evlist__alloc_aggr_stats(struct evlist *evlist, int nr_aggr);
> >  void evlist__reset_aggr_stats(struct evlist *evlist);
> > +void evlist__copy_res_stats(struct perf_stat_config *config, struct evlist *evlist);
> >
> >  int perf_stat_process_counter(struct perf_stat_config *config,
> >                             struct evsel *counter);
> > --
> > 2.41.0.162.gfafddb0af9-goog
> >