linux-kernel - Re: [PATCH v3 2/4] perf counts: Reset prev_raw

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Date:   Thu, 7 May 2020 17:19:32 +0200
From:   Jiri Olsa <jolsa@...hat.com>
To:     Jin Yao <yao.jin@...ux.intel.com>
Cc:     acme@...nel.org, jolsa@...nel.org, peterz@...radead.org,
        mingo@...hat.com, alexander.shishkin@...ux.intel.com,
        Linux-kernel@...r.kernel.org, ak@...ux.intel.com,
        kan.liang@...el.com, yao.jin@...el.com
Subject: Re: [PATCH v3 2/4] perf counts: Reset prev_raw_counts counts

On Thu, May 07, 2020 at 02:58:20PM +0800, Jin Yao wrote:
> The evsel->prev_raw_counts is updated in perf_evsel__compute_deltas:
> 
> perf_evsel__compute_deltas()
> {
> 	tmp = *perf_counts(evsel->prev_raw_counts, cpu, thread);
> 	*perf_counts(evsel->prev_raw_counts, cpu, thread) = *count;
> }
> 
> When we want to reset the evsel->prev_raw_counts in
> perf_evsel__reset_prev_raw_counts, zeroing the aggr is not enough,
> we need to reset the counts too.
> 
> Signed-off-by: Jin Yao <yao.jin@...ux.intel.com>
> ---
>  tools/perf/util/counts.c | 5 +++++
>  tools/perf/util/counts.h | 2 ++
>  tools/perf/util/stat.c   | 1 +
>  3 files changed, 8 insertions(+)
> 
> diff --git a/tools/perf/util/counts.c b/tools/perf/util/counts.c
> index f94e1a23dad6..af3bf36f7c63 100644
> --- a/tools/perf/util/counts.c
> +++ b/tools/perf/util/counts.c
> @@ -64,3 +64,8 @@ void perf_evsel__free_counts(struct evsel *evsel)
>  	perf_counts__delete(evsel->counts);
>  	evsel->counts = NULL;
>  }
> +
> +void perf_evsel__reset_raw_counts(struct evsel *evsel)
> +{
> +	perf_counts__reset(evsel->prev_raw_counts);
> +}
> diff --git a/tools/perf/util/counts.h b/tools/perf/util/counts.h
> index 92196df4945f..15bb9acb7cb0 100644
> --- a/tools/perf/util/counts.h
> +++ b/tools/perf/util/counts.h
> @@ -42,4 +42,6 @@ void perf_evsel__reset_counts(struct evsel *evsel);
>  int perf_evsel__alloc_counts(struct evsel *evsel, int ncpus, int nthreads);
>  void perf_evsel__free_counts(struct evsel *evsel);
>  
> +void perf_evsel__reset_raw_counts(struct evsel *evsel);
> +
>  #endif /* __PERF_COUNTS_H */
> diff --git a/tools/perf/util/stat.c b/tools/perf/util/stat.c
> index 774468341851..89e541564ed5 100644
> --- a/tools/perf/util/stat.c
> +++ b/tools/perf/util/stat.c
> @@ -168,6 +168,7 @@ static void perf_evsel__reset_prev_raw_counts(struct evsel *evsel)
>  		evsel->prev_raw_counts->aggr.val = 0;
>  		evsel->prev_raw_counts->aggr.ena = 0;
>  		evsel->prev_raw_counts->aggr.run = 0;
> +		perf_evsel__reset_raw_counts(evsel);

that seems needed, but we have it scathered all over the place,
could you centralize the reset? the way I see it the perf_counts__reset
should zero all the members of struct perf_counts.. so also
the aggr values

it could also check for counts != NULL and we could call it
instead of:
  perf_evsel__reset_prev_raw_counts
    perf_evsel__reset_raw_counts
      perf_counts__reset

jirka