On Thu, Feb 8, 2024 at 7:14 PM <weilin.wang@intel.com> wrote:
>
> From: Weilin Wang <weilin.wang@intel.com>
>
> There are some special events like topdown events and TSC that are not
> described in pmu-event JSON files. Add support to handle this type of
> events. This should be considered as a temporary solution because including
> these events in JSON files would be a better solution.
>
> Signed-off-by: Weilin Wang <weilin.wang@intel.com>
> ---
> tools/perf/util/metricgroup.c | 38 ++++++++++++++++++++++++++++++++++-
> 1 file changed, 37 insertions(+), 1 deletion(-)
>
> diff --git a/tools/perf/util/metricgroup.c b/tools/perf/util/metricgroup.c
> index 660c6b9b5fa7..a0579b0f81e5 100644
> --- a/tools/perf/util/metricgroup.c
> +++ b/tools/perf/util/metricgroup.c
> @@ -160,6 +160,20 @@ struct metric {
>
> /* Maximum number of counters per PMU*/
> #define NR_COUNTERS 16
> +/* Special events that are not described in pmu-event JSON files.
> + * topdown-* and TSC use dedicated registers, set as free
> + * counter for grouping purpose
msr/tsc/ is a software event where reading the value is done by rdtsc.
Unlike tool events like duration_time we want msr/tsc/ in the group
with the other hardware events so its running/enabled time scaling
matches.
To some extent the topdown- events do exist in the json as
"TOPDOWN.*". Looking at
tools/perf/pmu-events/arch/x86/tigerlake/pipeline.json I see just
TOPDOWN.BACKEND_BOUND_SLOTS. Perhaps we can add the rest rather than
have a workaround here?
If topdown events are in json and msr/tsc/ is treated like a software
event, as we do here:
https://git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools-next.git/tree/tools/perf/util/parse-events.c?h=perf-tools-next#n1920
perhaps we don't need the special events category?
Thanks,
Ian
> + */
> +enum special_events {
> + TOPDOWN = 0,
> + TSC = 1,
> + SPECIAL_EVENT_MAX,
> +};
> +
> +static const char *const special_event_names[SPECIAL_EVENT_MAX] = {
> + "topdown-",
> + "TSC",
> +};
>
> /**
> * An event used in a metric. This info is for metric grouping.
> @@ -2102,6 +2116,15 @@ static int create_grouping(struct list_head *pmu_info_list,
> return ret;
> };
>
> +static bool is_special_event(const char *id)
> +{
> + for (int i = 0; i < SPECIAL_EVENT_MAX; i++) {
> + if (!strncmp(id, special_event_names[i], strlen(special_event_names[i])))
> + return true;
> + }
> + return false;
> +}
> +
> /**
> * hw_aware_build_grouping - Build event groupings by reading counter
> * requirement of the events and counter available on the system from
> @@ -2126,6 +2149,17 @@ static int hw_aware_build_grouping(struct expr_parse_ctx *ctx __maybe_unused,
> hashmap__for_each_entry(ctx->ids, cur, bkt) {
> const char *id = cur->pkey;
>
> + if (is_special_event(id)) {
> + struct metricgroup__event_info *event;
> +
> + event = event_info__new(id, "default_core", "0",
> + /*free_counter=*/true);
> + if (!event)
> + goto err_out;
> +
> + list_add(&event->nd, &event_info_list);
> + continue;
> + }
> ret = get_metricgroup_events(id, etable, &event_info_list);
> if (ret)
> goto err_out;
> @@ -2597,8 +2631,10 @@ int metricgroup__parse_groups(struct evlist *perf_evlist,
> ret = hw_aware_parse_groups(perf_evlist, pmu, str,
> metric_no_threshold, user_requested_cpu_list, system_wide,
> /*fake_pmu=*/NULL, metric_events, table);
> - if (!ret)
> + if (!ret) {
> + pr_info("Hardware aware grouping completed\n");
> return 0;
> + }
> }
>
> return parse_groups(perf_evlist, pmu, str, metric_no_group, metric_no_merge,
> --
> 2.42.0
>