Re: [RFC PATCH v4 3/6] perf stat: Add retire latency values into the expr_parse_ctx to prepare for final metric calculation

[Ian Rogers]

On Tue, Mar 12, 2024 at 4:49 PM <weilin.wang@xxxxxxxxx> wrote:
>
> From: Weilin Wang <weilin.wang@xxxxxxxxx>
>
> Retire latency values of events are used in metric formulas. This update adds
> code to process data from perf record for required retire latency values.
>
> Signed-off-by: Weilin Wang <weilin.wang@xxxxxxxxx>
> ---
>  tools/perf/builtin-stat.c     |  1 +
>  tools/perf/util/metricgroup.h |  1 +
>  tools/perf/util/stat-shadow.c | 19 +++++++++++++++++++
>  3 files changed, 21 insertions(+)
>
> diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
> index 4e92e73cbeaf..a479b21874b0 100644
> --- a/tools/perf/builtin-stat.c
> +++ b/tools/perf/builtin-stat.c
> @@ -786,6 +786,7 @@ static int process_sample_event(struct perf_tool *tool __maybe_unused,
>                 if (!strcmp(evname, t->name)) {
>                         t->count += 1;
>                         t->sum += sample->retire_lat;
> +                       t->val = (double) t->sum / t->count;
>                         break;
>                 }
>         }
> diff --git a/tools/perf/util/metricgroup.h b/tools/perf/util/metricgroup.h
> index 3c37d80c4d34..38f9134d8b54 100644
> --- a/tools/perf/util/metricgroup.h
> +++ b/tools/perf/util/metricgroup.h
> @@ -82,6 +82,7 @@ struct tpebs_retire_lat {
>         const char *tpebs_name;
>         size_t count;
>         int sum;
> +       double val;

Given the similarity of count, sum and val it would be good to document them.

>  };
>
>  struct metric_event *metricgroup__lookup(struct rblist *metric_events,
> diff --git a/tools/perf/util/stat-shadow.c b/tools/perf/util/stat-shadow.c
> index 3466aa952442..8fc3415de106 100644
> --- a/tools/perf/util/stat-shadow.c
> +++ b/tools/perf/util/stat-shadow.c
> @@ -355,6 +355,20 @@ static void print_nsecs(struct perf_stat_config *config,
>                 print_metric(config, ctxp, NULL, NULL, "CPUs utilized", 0);
>  }
>
> +static int prepare_retire_lat(struct expr_parse_ctx *pctx,
> +                            struct list_head *retire_lats)
> +{
> +       int ret = 0;
> +       struct tpebs_retire_lat *t;
> +
> +       list_for_each_entry(t, retire_lats, nd) {
> +               ret = expr__add_id_val(pctx, strdup(t->tpebs_name), t->val);
> +               if (ret < 0)
> +                       return ret;
> +       }
> +       return ret;
> +}
> +
>  static int prepare_metric(const struct metric_expr *mexp,
>                           const struct evsel *evsel,
>                           struct expr_parse_ctx *pctx,
> @@ -486,6 +500,11 @@ static void generic_metric(struct perf_stat_config *config,
>                 pctx->sctx.user_requested_cpu_list = strdup(config->user_requested_cpu_list);
>         pctx->sctx.runtime = runtime;
>         pctx->sctx.system_wide = config->system_wide;
> +       i = prepare_retire_lat(pctx, &config->tpebs_results);
> +       if (i < 0) {
> +               expr__ctx_free(pctx);
> +               return;
> +       }
>         i = prepare_metric(mexp, evsel, pctx, aggr_idx);
>         if (i < 0) {
>                 expr__ctx_free(pctx);
> --
> 2.43.0
>