Commit dcc81be0 authored by Ian Rogers's avatar Ian Rogers Committed by Arnaldo Carvalho de Melo
Browse files

perf metricgroup: Fix uncore metric expressions 



A metric like DRAM_BW_Use has on SkylakeX events uncore_imc/cas_count_read/
and uncore_imc/case_count_write/.

These events open 6 events per socket with pmu names of
uncore_imc_[0-5].

The current metric setup code in find_evsel_group assumes one ID will
map to 1 event to be recorded in metric_events.

For events with multiple matches, the first event is recorded in
metric_events (avoiding matching >1 event with the same name) and the
evlist_used updated so that duplicate events aren't removed when the
evlist has unused events removed.

Before this change:

  $ /tmp/perf/perf stat -M DRAM_BW_Use -a -- sleep 1

   Performance counter stats for 'system wide':

               41.14 MiB  uncore_imc/cas_count_read/
       1,002,614,251 ns   duration_time

         1.002614251 seconds time elapsed

After this change:

  $ /tmp/perf/perf stat -M DRAM_BW_Use -a -- sleep 1

   Performance counter stats for 'system wide':

              157.47 MiB  uncore_imc/cas_count_read/ #     0.00 DRAM_BW_Use
              126.97 MiB  uncore_imc/cas_count_write/
       1,003,019,728 ns   duration_time

Erroneous duplication introduced in:
commit 2440689d ("perf metricgroup: Remove duped metric group events").

Fixes: ded80bda ("perf expr: Migrate expr ids table to a hashmap").
Reported-by: default avatarJin Yao <yao.jin@linux.intel.com>
Signed-off-by: default avatarIan Rogers <irogers@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Andrii Nakryiko <andriin@fb.com>
Cc: Athira Jajeev <atrajeev@linux.vnet.ibm.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: John Fastabend <john.fastabend@gmail.com>
Cc: KP Singh <kpsingh@chromium.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Martin KaFai Lau <kafai@fb.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Song Liu <songliubraving@fb.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Yonghong Song <yhs@fb.com>
Cc: bpf@vger.kernel.org
Cc: netdev@vger.kernel.org
Link: http://lore.kernel.org/lkml/20200917201807.4090224-1-irogers@google.com


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 0f1b550e

tools/perf/util/metricgroup.c

+56 −19
Original line number Diff line number Diff line
@@ -150,6 +150,18 @@ static void expr_ids__exit(struct expr_ids *ids) 
		free(ids->id[i].id);

}



static bool contains_event(struct evsel **metric_events, int num_events,

			const char *event_name)

{

	int i;



	for (i = 0; i < num_events; i++) {

		if (!strcmp(metric_events[i]->name, event_name))

			return true;

	}

	return false;

}



/**

 * Find a group of events in perf_evlist that correpond to those from a parsed

 * metric expression. Note, as find_evsel_group is called in the same order as
@@ -180,7 +192,11 @@ static struct evsel *find_evsel_group(struct evlist *perf_evlist, 
	int i = 0, matched_events = 0, events_to_match;

	const int idnum = (int)hashmap__size(&pctx->ids);



	/* duration_time is grouped separately. */

	/*

	 * duration_time is always grouped separately, when events are grouped

	 * (ie has_constraint is false) then ignore it in the matching loop and

	 * add it to metric_events at the end.

	 */

	if (!has_constraint &&

	    hashmap__find(&pctx->ids, "duration_time", (void **)&val_ptr))

		events_to_match = idnum - 1;
@@ -207,23 +223,20 @@ static struct evsel *find_evsel_group(struct evlist *perf_evlist, 
				sizeof(struct evsel *) * idnum);

			current_leader = ev->leader;

		}

		if (hashmap__find(&pctx->ids, ev->name, (void **)&val_ptr)) {

			if (has_constraint) {

		/*

				 * Events aren't grouped, ensure the same event

				 * isn't matched from two groups.

		 * Check for duplicate events with the same name. For example,

		 * uncore_imc/cas_count_read/ will turn into 6 events per socket

		 * on skylakex. Only the first such event is placed in

		 * metric_events. If events aren't grouped then this also

		 * ensures that the same event in different sibling groups

		 * aren't both added to metric_events.

		 */

				for (i = 0; i < matched_events; i++) {

					if (!strcmp(ev->name,

						    metric_events[i]->name)) {

						break;

					}

				}

				if (i != matched_events)

		if (contains_event(metric_events, matched_events, ev->name))

			continue;

			}

		/* Does this event belong to the parse context? */

		if (hashmap__find(&pctx->ids, ev->name, (void **)&val_ptr))

			metric_events[matched_events++] = ev;

		}



		if (matched_events == events_to_match)

			break;

	}
@@ -239,7 +252,7 @@ static struct evsel *find_evsel_group(struct evlist *perf_evlist, 
	}



	if (matched_events != idnum) {

		/* Not whole match */

		/* Not a whole match */

		return NULL;

	}
@@ -247,8 +260,32 @@ static struct evsel *find_evsel_group(struct evlist *perf_evlist, 


	for (i = 0; i < idnum; i++) {

		ev = metric_events[i];

		/* Don't free the used events. */

		set_bit(ev->idx, evlist_used);

		/*

		 * The metric leader points to the identically named event in

		 * metric_events.

		 */

		ev->metric_leader = ev;

		/*

		 * Mark two events with identical names in the same group (or

		 * globally) as being in use as uncore events may be duplicated

		 * for each pmu. Set the metric leader of such events to be the

		 * event that appears in metric_events.

		 */

		evlist__for_each_entry_continue(perf_evlist, ev) {

			/*

			 * If events are grouped then the search can terminate

			 * when then group is left.

			 */

			if (!has_constraint &&

			    ev->leader != metric_events[i]->leader)

				break;

			if (!strcmp(metric_events[i]->name, ev->name)) {

				set_bit(ev->idx, evlist_used);

				ev->metric_leader = metric_events[i];

			}

		}

	}



	return metric_events[0];