linux-kernel - [PATCH] perf stat: Merge uncore events by default for hybrid platform

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Message-Id: <20210616063004.2824-1-yao.jin@linux.intel.com>
Date:   Wed, 16 Jun 2021 14:30:04 +0800
From:   Jin Yao <yao.jin@...ux.intel.com>
To:     acme@...nel.org, jolsa@...nel.org, peterz@...radead.org,
        mingo@...hat.com, alexander.shishkin@...ux.intel.com
Cc:     Linux-kernel@...r.kernel.org, ak@...ux.intel.com,
        kan.liang@...el.com, yao.jin@...el.com,
        Jin Yao <yao.jin@...ux.intel.com>
Subject: [PATCH] perf stat: Merge uncore events by default for hybrid platform

On hybrid platform, by default 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

While 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' still works 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@...ux.intel.com>
---
 tools/perf/builtin-stat.c      |  3 ---
 tools/perf/util/stat-display.c | 29 +++++++++++++++++++++++++----
 2 files changed, 25 insertions(+), 7 deletions(-)

diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
index f9f74a514315..b67a44982b61 100644
--- a/tools/perf/builtin-stat.c
+++ b/tools/perf/builtin-stat.c
@@ -2442,9 +2442,6 @@ int cmd_stat(int argc, const char **argv)
 
 	evlist__check_cpu_maps(evsel_list);
 
-	if (perf_pmu__has_hybrid())
-		stat_config.no_merge = true;
-
 	/*
 	 * Initialize thread_map with comm names,
 	 * so we could print it out on output.
diff --git a/tools/perf/util/stat-display.c b/tools/perf/util/stat-display.c
index b759dfd633b4..c6070f4684ca 100644
--- a/tools/perf/util/stat-display.c
+++ b/tools/perf/util/stat-display.c
@@ -595,6 +595,19 @@ static void collect_all_aliases(struct perf_stat_config *config, struct evsel *c
 	}
 }
 
+static bool is_uncore(struct evsel *evsel)
+{
+	struct perf_pmu *pmu;
+
+	if (evsel->pmu_name) {
+		pmu = perf_pmu__find(evsel->pmu_name);
+		if (pmu)
+			return pmu->is_uncore;
+	}
+
+	return false;
+}
+
 static bool collect_data(struct perf_stat_config *config, struct evsel *counter,
 			    void (*cb)(struct perf_stat_config *config, struct evsel *counter, void *data,
 				       bool first),
@@ -603,10 +616,18 @@ static bool collect_data(struct perf_stat_config *config, struct evsel *counter,
 	if (counter->merged_stat)
 		return false;
 	cb(config, counter, data, true);
-	if (config->no_merge)
-		uniquify_event_name(counter);
-	else if (counter->auto_merge_stats)
-		collect_all_aliases(config, counter, cb, data);
+	if (perf_pmu__has_hybrid()) {
+		if (config->no_merge || !is_uncore(counter))
+			uniquify_event_name(counter);
+		else if (counter->auto_merge_stats)
+			collect_all_aliases(config, counter, cb, data);
+	} else {
+		if (config->no_merge)
+			uniquify_event_name(counter);
+		else if (counter->auto_merge_stats)
+			collect_all_aliases(config, counter, cb, data);
+	}
+
 	return true;
 }
 
-- 
2.17.1