linux-kernel - [PATCH] perf list: Skip the invalid hybrid pmu

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Message-Id: <20210610051646.4003-1-yao.jin@linux.intel.com>
Date:   Thu, 10 Jun 2021 13:16:46 +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 list: Skip the invalid hybrid pmu

On hybrid platform, such as Alderlake, if atom CPUs are offlined,
the kernel still exports the sysfs path '/sys/devices/cpu_atom/' for
'cpu_atom' pmu but the file '/sys/devices/cpu_atom/cpus' is empty,
which indicates this is an invalid pmu.

The perf-list needs to check and skip the invalid hybrid pmu.

Before:

  # perf list
  ...
  branch-instructions OR cpu_atom/branch-instructions/ [Kernel PMU event]
  branch-instructions OR cpu_core/branch-instructions/ [Kernel PMU event]
  branch-misses OR cpu_atom/branch-misses/           [Kernel PMU event]
  branch-misses OR cpu_core/branch-misses/           [Kernel PMU event]
  bus-cycles OR cpu_atom/bus-cycles/                 [Kernel PMU event]
  bus-cycles OR cpu_core/bus-cycles/                 [Kernel PMU event]
  ...

The cpu_atom events are still displayed even if atom CPUs are offlined.

After:

  # perf list
  ...
  branch-instructions OR cpu_core/branch-instructions/ [Kernel PMU event]
  branch-misses OR cpu_core/branch-misses/           [Kernel PMU event]
  bus-cycles OR cpu_core/bus-cycles/                 [Kernel PMU event]
  ...

Now only cpu_core events are displayed.

Signed-off-by: Jin Yao <yao.jin@...ux.intel.com>
---
 tools/perf/util/pmu-hybrid.c | 11 +++++++++++
 tools/perf/util/pmu-hybrid.h |  2 ++
 tools/perf/util/pmu.c        |  3 +++
 3 files changed, 16 insertions(+)

diff --git a/tools/perf/util/pmu-hybrid.c b/tools/perf/util/pmu-hybrid.c
index f51ccaac60ee..fcc1182f8fe5 100644
--- a/tools/perf/util/pmu-hybrid.c
+++ b/tools/perf/util/pmu-hybrid.c
@@ -87,3 +87,14 @@ char *perf_pmu__hybrid_type_to_pmu(const char *type)
 	free(pmu_name);
 	return NULL;
 }
+
+bool perf_pmu__is_invalid_hybrid(const char *name)
+{
+	if (strncmp(name, "cpu_", 4))
+		return false;
+
+	if (perf_pmu__hybrid_mounted(name))
+		return false;
+
+	return true;
+}
diff --git a/tools/perf/util/pmu-hybrid.h b/tools/perf/util/pmu-hybrid.h
index 2b186c26a43e..8261a312c854 100644
--- a/tools/perf/util/pmu-hybrid.h
+++ b/tools/perf/util/pmu-hybrid.h
@@ -30,4 +30,6 @@ static inline int perf_pmu__hybrid_pmu_num(void)
 	return num;
 }

+bool perf_pmu__is_invalid_hybrid(const char *name);
+
 #endif /* __PMU_HYBRID_H */
diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
index 88c8ecdc60b0..281670e9c4bd 100644
--- a/tools/perf/util/pmu.c
+++ b/tools/perf/util/pmu.c
@@ -1604,6 +1604,9 @@ void print_pmu_events(const char *event_glob, bool name_only, bool quiet_flag,
 	pmu = NULL;
 	j = 0;
 	while ((pmu = perf_pmu__scan(pmu)) != NULL) {
+		if (perf_pmu__is_invalid_hybrid(pmu->name))
+			continue;
+
 		list_for_each_entry(alias, &pmu->aliases, list) {
 			char *name = alias->desc ? alias->name :
 				format_alias(buf, sizeof(buf), pmu, alias);
-- 
2.17.1