Re: [RFC PATCH v4 06/15] perf stat: Add functions to get counter info

[Ian Rogers]

On Thu, Feb 8, 2024 at 7:14 PM <weilin.wang@xxxxxxxxx> wrote:
>
> From: Weilin Wang <weilin.wang@xxxxxxxxx>
>
> Add data structure metricgroup__pmu_counters to represent hardware counters
> available in the system.
>
> Add functions to parse pmu-events and create the list of pmu_info_list to
> hold the counter information of the system.
>
> Add functions to free pmu_info_list and event_info_list before exit
> grouping for hardware-grouping method
>
> This method would fall back to normal grouping when event json files do not
> support hardware aware grouping.
>
> Signed-off-by: Weilin Wang <weilin.wang@xxxxxxxxx>

Reviewed-by: Ian Rogers <irogers@xxxxxxxxxx>

Thanks,
Ian

> ---
>  tools/perf/util/metricgroup.c | 101 ++++++++++++++++++++++++++++++++--
>  1 file changed, 97 insertions(+), 4 deletions(-)
>
> diff --git a/tools/perf/util/metricgroup.c b/tools/perf/util/metricgroup.c
> index 2a917220fb34..9061ed4ca015 100644
> --- a/tools/perf/util/metricgroup.c
> +++ b/tools/perf/util/metricgroup.c
> @@ -179,6 +179,20 @@ struct metricgroup__event_info {
>         DECLARE_BITMAP(counters, NR_COUNTERS);
>  };
>
> +/**
> + * A node is the counter availability of a pmu.
> + * This info is built up at the beginning from JSON file and
> + * used as a reference in metric grouping process.
> + */
> +struct metricgroup__pmu_counters {
> +       struct list_head nd;
> +       /** The name of the pmu the event collected on. */
> +       const char *name;
> +       /** The number of gp counters in the pmu. */
> +       size_t num_counters;
> +       size_t num_fixed_counters;
> +};
> +
>  /**
>   * Each group is one node in the group string list.
>   */
> @@ -1530,6 +1544,27 @@ static int parse_counter(const char *counter,
>         return 0;
>  }
>
> +static void metricgroup__free_event_info(struct list_head
> +                                       *event_info_list)
> +{
> +       struct metricgroup__event_info *e, *tmp;
> +
> +       list_for_each_entry_safe(e, tmp, event_info_list, nd) {
> +               list_del_init(&e->nd);
> +               free(e);
> +       }
> +}
> +
> +static void metricgroup__free_pmu_info(struct list_head *pmu_info_list)
> +{
> +       struct metricgroup__pmu_counters *p, *tmp;
> +
> +       list_for_each_entry_safe(p, tmp, pmu_info_list, nd) {
> +               list_del_init(&p->nd);
> +               free(p);
> +       }
> +}
> +
>  static struct metricgroup__event_info *event_info__new(const char *name,
>                                                       const char *pmu_name,
>                                                       const char *counter,
> @@ -1548,7 +1583,7 @@ static struct metricgroup__event_info *event_info__new(const char *name,
>
>         e->name = name;
>         e->free_counter = free_counter;
> -       e->pmu_name = strdup(pmu_name);
> +       e->pmu_name = pmu_name;
>         if (free_counter) {
>                 ret = set_counter_bitmap(0, e->counters);
>                 if (ret)
> @@ -1583,7 +1618,9 @@ static int metricgroup__add_metric_event_callback(const struct pmu_event *pe,
>         struct metricgroup__add_metric_event_data *d = data;
>
>         if (!strcasecmp(pe->name, d->event_name)) {
> -               event = event_info__new(d->event_id, pe->pmu, pe->counter, /*free_counter=*/false);
> +               if (!pe->counters)
> +                       return -EINVAL;
> +               event = event_info__new(d->event_id, pe->pmu, pe->counters, /*free_counter=*/false);
>                 if (!event)
>                         return -ENOMEM;
>                 list_add(&event->nd, d->list);
> @@ -1622,7 +1659,7 @@ static int get_metricgroup_events(const char *full_id,
>                         .event_name = id,
>                         .event_id = full_id,
>                 };
> -               ret = pmu_events_table_for_each_event(table,
> +               ret = pmu_events_table__for_each_event(table, /*pmu=*/NULL,
>                                 metricgroup__add_metric_event_callback, &data);
>         }
>
> @@ -1631,6 +1668,57 @@ static int get_metricgroup_events(const char *full_id,
>         return ret;
>  }
>
> +static struct metricgroup__pmu_counters *pmu_layout__new(const struct pmu_layout *pl)
> +{
> +       struct metricgroup__pmu_counters *l;
> +
> +       l = zalloc(sizeof(*l));
> +
> +       if (!l)
> +               return NULL;
> +
> +       l->name = pl->pmu;
> +       l->num_counters = pl->num_counters;
> +       l->num_fixed_counters = pl->num_fixed_counters;
> +       pr_debug("create new pmu_layout: [pmu]=%s, [gp_size]=%ld, [fixed_size]=%ld\n",
> +               l->name, l->num_counters, l->num_fixed_counters);
> +       return l;
> +}
> +
> +static int metricgroup__add_pmu_layout_callback(const struct pmu_layout *pl,
> +                                               void *data)
> +{
> +       struct metricgroup__pmu_counters *pmu;
> +       struct list_head *d = data;
> +       int ret = 0;
> +
> +       pmu = pmu_layout__new(pl);
> +       if (!pmu)
> +               return -ENOMEM;
> +       list_add(&pmu->nd, d);
> +       return ret;
> +}
> +
> +/**
> + * get_pmu_counter_layouts - Find counter info of the architecture from
> + * the pmu_layouts table
> + * @pmu_info_list: the list that the new counter info of a pmu is added to.
> + * @table: pmu_layouts table that is searched for counter info.
> + */
> +static int get_pmu_counter_layouts(struct list_head *pmu_info_list,
> +                                  const struct pmu_layouts_table
> +                                  *table)
> +{
> +       LIST_HEAD(list);
> +       int ret;
> +
> +       ret = pmu_layouts_table__for_each_layout(table,
> +                                               metricgroup__add_pmu_layout_callback, &list);
> +
> +       list_splice(&list, pmu_info_list);
> +       return ret;
> +}
> +
>  /**
>   * hw_aware_build_grouping - Build event groupings by reading counter
>   * requirement of the events and counter available on the system from
> @@ -1649,6 +1737,7 @@ static int hw_aware_build_grouping(struct expr_parse_ctx *ctx __maybe_unused,
>         LIST_HEAD(event_info_list);
>         size_t bkt;
>         const struct pmu_events_table *etable = perf_pmu__find_events_table(NULL);
> +       const struct pmu_layouts_table *ltable = perf_pmu__find_layouts_table(NULL);
>
>  #define RETURN_IF_NON_ZERO(x) do { if (x) return x; } while (0)
>         hashmap__for_each_entry(ctx->ids, cur, bkt) {
> @@ -1658,9 +1747,13 @@ static int hw_aware_build_grouping(struct expr_parse_ctx *ctx __maybe_unused,
>
>                 ret = get_metricgroup_events(id, etable, &event_info_list);
>                 if (ret)
> -                       return ret;
> +                       goto err_out;
>         }
> +       ret = get_pmu_counter_layouts(&pmu_info_list, ltable);
>
> +err_out:
> +       metricgroup__free_event_info(&event_info_list);
> +       metricgroup__free_pmu_info(&pmu_info_list);
>         return ret;
>  #undef RETURN_IF_NON_ZERO
>  }
> --
> 2.42.0
>