Re: [RFC PATCH v3 1/6] perf stat: Parse and find tpebs events when parsing metrics to prepare for perf record sampling

[Namhyung Kim]

On Fri, Mar 1, 2024 at 4:11 PM <weilin.wang@xxxxxxxxx> wrote:
>
> From: Weilin Wang <weilin.wang@xxxxxxxxx>
>
> Metrics that use tpebs values would use the :retire_latency keyword in
> formulas. We put all these events into a list and pass the list to perf
> record to collect their retire latency value.
>
> Signed-off-by: Weilin Wang <weilin.wang@xxxxxxxxx>
> ---
>  tools/perf/builtin-stat.c     | 38 +++++++++++++---
>  tools/perf/util/metricgroup.c | 81 +++++++++++++++++++++++++++++------
>  tools/perf/util/metricgroup.h | 10 ++++-
>  tools/perf/util/stat.h        |  2 +
>  4 files changed, 112 insertions(+), 19 deletions(-)
>
> diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
> index 6bba1a89d030..5a3093541cff 100644
> --- a/tools/perf/builtin-stat.c
> +++ b/tools/perf/builtin-stat.c
> @@ -162,6 +162,7 @@ static struct perf_stat_config stat_config = {
>         .ctl_fd                 = -1,
>         .ctl_fd_ack             = -1,
>         .iostat_run             = false,
> +       .tpebs_event_size = 0,

Usually you don't need to add 0 initial value as it's the default.


>  };
>
>  static bool cpus_map_matched(struct evsel *a, struct evsel *b)
> @@ -686,6 +687,12 @@ static enum counter_recovery stat_handle_error(struct evsel *counter)
>         return COUNTER_FATAL;
>  }
>
> +static int __run_perf_record(void)
> +{
> +       pr_debug("Prepare perf record for retire_latency\n");
> +       return 0;
> +}
> +
>  static int __run_perf_stat(int argc, const char **argv, int run_idx)
>  {
>         int interval = stat_config.interval;
> @@ -703,6 +710,15 @@ static int __run_perf_stat(int argc, const char **argv, int run_idx)
>         int err;
>         bool second_pass = false;
>
> +       //Prepare perf record for sampling event retire_latency before fork and prepare workload

We prefer C style comments /* ... */.


> +       if (stat_config.tpebs_event_size > 0) {
> +               int ret;
> +
> +               ret = __run_perf_record();
> +               if (ret)
> +                       return ret;
> +       }
> +
>         if (forks) {
>                 if (evlist__prepare_workload(evsel_list, &target, argv, is_pipe, workload_exec_failed_signal) < 0) {
>                         perror("failed to prepare workload");
> @@ -2106,7 +2122,9 @@ static int add_default_attributes(void)
>                                                 stat_config.metric_no_threshold,
>                                                 stat_config.user_requested_cpu_list,
>                                                 stat_config.system_wide,
> -                                               &stat_config.metric_events);
> +                                               &stat_config.metric_events,
> +                                               &stat_config.tpebs_events,
> +                                               &stat_config.tpebs_event_size);

Hmm.. the argument list is too long.  Maybe we need to think
about just passing a pointer to the stat_config instead.


>         }
>
>         if (smi_cost) {
> @@ -2139,7 +2157,9 @@ static int add_default_attributes(void)
>                                                 stat_config.metric_no_threshold,
>                                                 stat_config.user_requested_cpu_list,
>                                                 stat_config.system_wide,
> -                                               &stat_config.metric_events);
> +                                               &stat_config.metric_events,
> +                                               &stat_config.tpebs_events,
> +                                               &stat_config.tpebs_event_size);
>         }
>
>         if (topdown_run) {
> @@ -2173,7 +2193,9 @@ static int add_default_attributes(void)
>                                                 /*metric_no_threshold=*/true,
>                                                 stat_config.user_requested_cpu_list,
>                                                 stat_config.system_wide,
> -                                               &stat_config.metric_events) < 0)
> +                                               &stat_config.metric_events,
> +                                               &stat_config.tpebs_events,
> +                                               &stat_config.tpebs_event_size) < 0)
>                         return -1;
>         }
>
> @@ -2214,7 +2236,9 @@ static int add_default_attributes(void)
>                                                         /*metric_no_threshold=*/true,
>                                                         stat_config.user_requested_cpu_list,
>                                                         stat_config.system_wide,
> -                                                       &stat_config.metric_events) < 0)
> +                                                       &stat_config.metric_events,
> +                                                       /*&stat_config.tpebs_events=*/NULL,
> +                                                       /*stat_config.tpebs_event_size=*/0) < 0)
>                                 return -1;
>
>                         evlist__for_each_entry(metric_evlist, metric_evsel) {
> @@ -2736,6 +2760,8 @@ int cmd_stat(int argc, const char **argv)
>                 }
>         }
>
> +       INIT_LIST_HEAD(&stat_config.tpebs_events);

You can move it to the initializer using LIST_HEAD_INIT().

> +
>         /*
>          * Metric parsing needs to be delayed as metrics may optimize events
>          * knowing the target is system-wide.
> @@ -2748,7 +2774,9 @@ int cmd_stat(int argc, const char **argv)
>                                                 stat_config.metric_no_threshold,
>                                                 stat_config.user_requested_cpu_list,
>                                                 stat_config.system_wide,
> -                                               &stat_config.metric_events);
> +                                               &stat_config.metric_events,
> +                                               &stat_config.tpebs_events,
> +                                               &stat_config.tpebs_event_size);
>
>                 zfree(&metrics);
>                 if (ret) {
> diff --git a/tools/perf/util/metricgroup.c b/tools/perf/util/metricgroup.c
> index b24a1c177a80..5ee96d2f16c9 100644
> --- a/tools/perf/util/metricgroup.c
> +++ b/tools/perf/util/metricgroup.c
> @@ -277,7 +277,8 @@ static bool contains_metric_id(struct evsel **metric_events, int num_events,
>   */
>  static int setup_metric_events(const char *pmu, struct hashmap *ids,
>                                struct evlist *metric_evlist,
> -                              struct evsel ***out_metric_events)
> +                              struct evsel ***out_metric_events,
> +                              size_t tpebs_event_size)
>  {
>         struct evsel **metric_events;
>         const char *metric_id;
> @@ -286,7 +287,7 @@ static int setup_metric_events(const char *pmu, struct hashmap *ids,
>         bool all_pmus = !strcmp(pmu, "all") || perf_pmus__num_core_pmus() == 1 || !is_pmu_core(pmu);
>
>         *out_metric_events = NULL;
> -       ids_size = hashmap__size(ids);
> +       ids_size = hashmap__size(ids) - tpebs_event_size;
>
>         metric_events = calloc(ids_size + 1, sizeof(void *));
>         if (!metric_events)
> @@ -323,6 +324,7 @@ static int setup_metric_events(const char *pmu, struct hashmap *ids,
>                 }
>         }
>         if (matched_events < ids_size) {
> +               pr_debug("Error: matched_events = %lu, ids_size = %lu\n", matched_events, ids_size);
>                 free(metric_events);
>                 return -EINVAL;
>         }
> @@ -670,7 +672,9 @@ static int decode_all_metric_ids(struct evlist *perf_evlist, const char *modifie
>  static int metricgroup__build_event_string(struct strbuf *events,
>                                            const struct expr_parse_ctx *ctx,
>                                            const char *modifier,
> -                                          bool group_events)
> +                                          bool group_events,
> +                                          struct list_head *tpebs_events __maybe_unused,
> +                                          size_t *tpebs_event_size)
>  {
>         struct hashmap_entry *cur;
>         size_t bkt;
> @@ -683,8 +687,47 @@ static int metricgroup__build_event_string(struct strbuf *events,
>         hashmap__for_each_entry(ctx->ids, cur, bkt) {
>                 const char *sep, *rsep, *id = cur->pkey;
>                 enum perf_tool_event ev;
> +               char *p = strstr(id, ":R");
> +               char *p1 = strstr(id, "@R");

Can you please add a comment on what you are doing here?

> +
> +               if (p == NULL && p1) {
> +                       p = strstr(p1+1, "@R");
> +                       if (p == NULL)
> +                               p = p1;
> +                       p = p+1;
> +               }
> +
> +               if (p) {
> +                       struct tpebs_event *new_event = malloc(sizeof(struct tpebs_event));
> +                       char *name;
> +                       char *at;
>
> -               pr_debug("found event %s\n", id);
> +                       pr_debug("event name %s\n", id);
> +                       new_event->tpebs_name = strdup(id);
> +                       *p = '\0';
> +                       name = malloc(strlen(id) + 2);
> +                       if (!name)
> +                               return -ENOMEM;

Note the previous two allocations can also fail. :)

> +
> +                       at = strchr(id, '@');
> +                       if (at != NULL) {
> +                               pr_debug("tpebs name %s\n", id);
> +                               *at = '/';
> +                               at = strchr(id, '@');
> +                               *at = '/';
> +                               strcpy(name, id);
> +                               strcat(name, "p");
> +                       } else {
> +                               strcpy(name, id);
> +                               strcat(name, ":p");
> +                       }
> +                       new_event->name = name;
> +                       *tpebs_event_size += 1;
> +                       pr_debug("retire_latency required, tpebs_event_size=%lu, new_event=%s\n",
> +                       *tpebs_event_size, new_event->name);

Broken indentation.


> +                       list_add_tail(&new_event->nd, tpebs_events);
> +                       continue;
> +               }
>
>                 /* Always move tool events outside of the group. */
>                 ev = perf_tool_event__from_str(id);
> @@ -1449,7 +1492,8 @@ static int build_combined_expr_ctx(const struct list_head *metric_list,
>  static int parse_ids(bool metric_no_merge, struct perf_pmu *fake_pmu,
>                      struct expr_parse_ctx *ids, const char *modifier,
>                      bool group_events, const bool tool_events[PERF_TOOL_MAX],
> -                    struct evlist **out_evlist)
> +                    struct evlist **out_evlist, struct list_head *tpebs_events,
> +                    size_t *tpebs_event_size)
>  {
>         struct parse_events_error parse_error;
>         struct evlist *parsed_evlist;
> @@ -1492,7 +1536,7 @@ static int parse_ids(bool metric_no_merge, struct perf_pmu *fake_pmu,
>                 }
>         }
>         ret = metricgroup__build_event_string(&events, ids, modifier,
> -                                             group_events);
> +                                             group_events, tpebs_events, tpebs_event_size);
>         if (ret)
>                 return ret;
>
> @@ -1531,7 +1575,9 @@ static int parse_groups(struct evlist *perf_evlist,
>                         bool system_wide,
>                         struct perf_pmu *fake_pmu,
>                         struct rblist *metric_events_list,
> -                       const struct pmu_metrics_table *table)
> +                       const struct pmu_metrics_table *table,
> +                       struct list_head *tpebs_events,
> +                       size_t *tpebs_event_size)
>  {
>         struct evlist *combined_evlist = NULL;
>         LIST_HEAD(metric_list);
> @@ -1563,7 +1609,8 @@ static int parse_groups(struct evlist *perf_evlist,
>                                         /*modifier=*/NULL,
>                                         /*group_events=*/false,
>                                         tool_events,
> -                                       &combined_evlist);
> +                                       &combined_evlist,
> +                                       tpebs_events, tpebs_event_size);
>                 }
>                 if (combined)
>                         expr__ctx_free(combined);
> @@ -1618,14 +1665,15 @@ static int parse_groups(struct evlist *perf_evlist,
>                 }
>                 if (!metric_evlist) {
>                         ret = parse_ids(metric_no_merge, fake_pmu, m->pctx, m->modifier,
> -                                       m->group_events, tool_events, &m->evlist);
> +                                       m->group_events, tool_events, &m->evlist,
> +                                       tpebs_events, tpebs_event_size);
>                         if (ret)
>                                 goto out;
>
>                         metric_evlist = m->evlist;
>                 }
>                 ret = setup_metric_events(fake_pmu ? "all" : m->pmu, m->pctx->ids,
> -                                         metric_evlist, &metric_events);
> +                                         metric_evlist, &metric_events, *tpebs_event_size);
>                 if (ret) {
>                         pr_err("Cannot resolve IDs for %s: %s\n",
>                                 m->metric_name, m->metric_expr);
> @@ -1692,16 +1740,21 @@ int metricgroup__parse_groups(struct evlist *perf_evlist,
>                               bool metric_no_threshold,
>                               const char *user_requested_cpu_list,
>                               bool system_wide,
> -                             struct rblist *metric_events)
> +                             struct rblist *metric_events,
> +                             struct list_head *tpebs_events,
> +                             size_t *tpebs_event_size)
>  {
>         const struct pmu_metrics_table *table = pmu_metrics_table__find();
>
> +       pr_debug("Test debugging\n");
> +

Can you please remove these debug messages before submitting?

Thanks,
Namhyung


>         if (!table)
>                 return -EINVAL;
>
>         return parse_groups(perf_evlist, pmu, str, metric_no_group, metric_no_merge,
>                             metric_no_threshold, user_requested_cpu_list, system_wide,
> -                           /*fake_pmu=*/NULL, metric_events, table);
> +                           /*fake_pmu=*/NULL, metric_events, table, tpebs_events,
> +                           tpebs_event_size);
>  }
>
>  int metricgroup__parse_groups_test(struct evlist *evlist,
> @@ -1715,7 +1768,9 @@ int metricgroup__parse_groups_test(struct evlist *evlist,
>                             /*metric_no_threshold=*/false,
>                             /*user_requested_cpu_list=*/NULL,
>                             /*system_wide=*/false,
> -                           &perf_pmu__fake, metric_events, table);
> +                           &perf_pmu__fake, metric_events, table,
> +                           /*tpebs_events=*/NULL,
> +                           /*tpebs_event_size=*/0);
>  }
>
>  struct metricgroup__has_metric_data {
> diff --git a/tools/perf/util/metricgroup.h b/tools/perf/util/metricgroup.h
> index d5325c6ec8e1..7c24ed768ff3 100644
> --- a/tools/perf/util/metricgroup.h
> +++ b/tools/perf/util/metricgroup.h
> @@ -66,6 +66,12 @@ struct metric_expr {
>         int runtime;
>  };
>
> +struct tpebs_event {
> +       struct list_head nd;
> +       const char *name;
> +       const char *tpebs_name;
> +};
> +
>  struct metric_event *metricgroup__lookup(struct rblist *metric_events,
>                                          struct evsel *evsel,
>                                          bool create);
> @@ -77,7 +83,9 @@ int metricgroup__parse_groups(struct evlist *perf_evlist,
>                               bool metric_no_threshold,
>                               const char *user_requested_cpu_list,
>                               bool system_wide,
> -                             struct rblist *metric_events);
> +                             struct rblist *metric_events,
> +                             struct list_head *tpebs_events,
> +                             size_t *tpebs_event_size);
>  int metricgroup__parse_groups_test(struct evlist *evlist,
>                                    const struct pmu_metrics_table *table,
>                                    const char *str,
> diff --git a/tools/perf/util/stat.h b/tools/perf/util/stat.h
> index d6e5c8787ba2..b987960df3c5 100644
> --- a/tools/perf/util/stat.h
> +++ b/tools/perf/util/stat.h
> @@ -109,6 +109,8 @@ struct perf_stat_config {
>         struct cpu_aggr_map     *cpus_aggr_map;
>         u64                     *walltime_run;
>         struct rblist            metric_events;
> +       struct list_head         tpebs_events;
> +       size_t                   tpebs_event_size;
>         int                      ctl_fd;
>         int                      ctl_fd_ack;
>         bool                     ctl_fd_close;
> --
> 2.43.0
>