Commit e0a7ef2a authored Jul 07, 2021 by Jin Yao Committed by Arnaldo Carvalho de Melo Jul 14, 2021

perf stat: Merge uncore events by default for hybrid platform



On a hybrid platform, by default 'perf stat' aggregates and reports the
event counts per PMU. For example,

  # perf stat -e cycles -a true

   Performance counter stats for 'system wide':

           1,400,445      cpu_core/cycles/
             680,881      cpu_atom/cycles/

         0.001770773 seconds time elapsed

But for uncore events that's not a suitable method. Uncore has nothing
to do with hybrid. So for uncore events, we aggregate event counts from
all PMUs and report the counts without PMUs.

Before:

  # perf stat -e arb/event=0x81,umask=0x1/,arb/event=0x84,umask=0x1/ -a true

   Performance counter stats for 'system wide':

               2,058      uncore_arb_0/event=0x81,umask=0x1/
               2,028      uncore_arb_1/event=0x81,umask=0x1/
                   0      uncore_arb_0/event=0x84,umask=0x1/
                   0      uncore_arb_1/event=0x84,umask=0x1/

         0.000614498 seconds time elapsed

After:

  # perf stat -e arb/event=0x81,umask=0x1/,arb/event=0x84,umask=0x1/ -a true

   Performance counter stats for 'system wide':

               3,996      arb/event=0x81,umask=0x1/
                   0      arb/event=0x84,umask=0x1/

         0.000630046 seconds time elapsed

Of course, we also keep the '--no-merge' working for uncore events.

  # perf stat -e arb/event=0x81,umask=0x1/,arb/event=0x84,umask=0x1/ --no-merge true

   Performance counter stats for 'system wide':

               1,952      uncore_arb_0/event=0x81,umask=0x1/
               1,921      uncore_arb_1/event=0x81,umask=0x1/
                   0      uncore_arb_0/event=0x84,umask=0x1/
                   0      uncore_arb_1/event=0x84,umask=0x1/

         0.000575536 seconds time elapsed

Signed-off-by: Jin Yao <yao.jin@linux.intel.com>
Acked-by: Jiri Olsa <jolsa@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20210707055652.962-1-yao.jin@linux.intel.com


Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

parent de3d5fd8

tools/perf/builtin-stat.c

+0 −3

Original line number	Original line	Diff line number	Diff line
	@@ -2445,9 +2445,6 @@ int cmd_stat(int argc, const char **argv)

	evlist__check_cpu_maps(evsel_list);		evlist__check_cpu_maps(evsel_list);

	if (perf_pmu__has_hybrid())
	stat_config.no_merge = true;

	/*		/*
	* Initialize thread_map with comm names,		* Initialize thread_map with comm names,
	* so we could print it out on output.		* so we could print it out on output.

tools/perf/util/stat-display.c

+13 −1

Original line number	Original line	Diff line number	Diff line
	@@ -596,6 +596,18 @@ static void collect_all_aliases(struct perf_stat_config config, struct evsel c
	}		}
	}		}

			static bool is_uncore(struct evsel *evsel)
			{
			struct perf_pmu *pmu = evsel__find_pmu(evsel);

			return pmu && pmu->is_uncore;
			}

			static bool hybrid_uniquify(struct evsel *evsel)
			{
			return perf_pmu__has_hybrid() && !is_uncore(evsel);
			}

	static bool collect_data(struct perf_stat_config config, struct evsel counter,		static bool collect_data(struct perf_stat_config config, struct evsel counter,
	void (cb)(struct perf_stat_config config, struct evsel counter, void data,		void (cb)(struct perf_stat_config config, struct evsel counter, void data,
	bool first),		bool first),
	@@ -604,7 +616,7 @@ static bool collect_data(struct perf_stat_config config, struct evsel counter,
	if (counter->merged_stat)		if (counter->merged_stat)
	return false;		return false;
	cb(config, counter, data, true);		cb(config, counter, data, true);
	if (config->no_merge)		if (config->no_merge \|\| hybrid_uniquify(counter))
	uniquify_event_name(counter);		uniquify_event_name(counter);
	else if (counter->auto_merge_stats)		else if (counter->auto_merge_stats)
	collect_all_aliases(config, counter, cb, data);		collect_all_aliases(config, counter, cb, data);