Messages in this thread | | | From | Ian Rogers <> | Date | Sat, 23 Mar 2024 22:20:05 -0700 | Subject | Re: [RFC PATCH v4 09/15] perf stat: Add function to handle special events in hardware-grouping |
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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 >
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