Commit 49afa7f6 authored by Jin Yao's avatar Jin Yao Committed by Arnaldo Carvalho de Melo
Browse files

perf pmu: Skip 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.

Need 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: default avatarJin Yao <yao.jin@linux.intel.com>
Acked-by: default avatarJiri Olsa <jolsa@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Jin Yao <yao.jin@intel.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lore.kernel.org/lkml/20210708013701.20347-2-yao.jin@linux.intel.com


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 40226a3d

tools/perf/util/pmu.c

+8 −1
Original line number Diff line number Diff line
@@ -950,6 +950,13 @@ static struct perf_pmu *pmu_lookup(const char *name) 
	LIST_HEAD(format);

	LIST_HEAD(aliases);

	__u32 type;

	bool is_hybrid = perf_pmu__hybrid_mounted(name);



	/*

	 * Check pmu name for hybrid and the pmu may be invalid in sysfs

	 */

	if (!strncmp(name, "cpu_", 4) && !is_hybrid)

		return NULL;



	/*

	 * The pmu data we store & need consists of the pmu
@@ -978,7 +985,7 @@ static struct perf_pmu *pmu_lookup(const char *name) 
	pmu->is_uncore = pmu_is_uncore(name);

	if (pmu->is_uncore)

		pmu->id = pmu_id(name);

	pmu->is_hybrid = perf_pmu__hybrid_mounted(name);

	pmu->is_hybrid = is_hybrid;

	pmu->max_precise = pmu_max_precise(name);

	pmu_add_cpu_aliases(&aliases, pmu);

	pmu_add_sys_aliases(&aliases, pmu);