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| author | Dapeng Mi <dapeng1.mi@linux.intel.com> | 2023-11-21 04:46:28 +0300 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2023-11-21 15:44:36 +0300 |
| commit | e8df9d9f4209c04161321d8c12640ae560f65939 (patch) | |
| tree | 860960b05fd0d46eb82ae60af6c3d14a5d04596a /arch | |
| parent | 98b1cc82c4affc16f5598d4fa14b1858671b2263 (diff) | |
| download | linux-e8df9d9f4209c04161321d8c12640ae560f65939.tar.xz | |
perf/x86/intel: Correct incorrect 'or' operation for PMU capabilities
When running perf-stat command on Intel hybrid platform, perf-stat
reports the following errors:
sudo taskset -c 7 ./perf stat -vvvv -e cpu_atom/instructions/ sleep 1
Opening: cpu/cycles/:HG
------------------------------------------------------------
perf_event_attr:
type 0 (PERF_TYPE_HARDWARE)
config 0xa00000000
disabled 1
------------------------------------------------------------
sys_perf_event_open: pid 0 cpu -1 group_fd -1 flags 0x8
sys_perf_event_open failed, error -16
Performance counter stats for 'sleep 1':
<not counted> cpu_atom/instructions/
It looks the cpu_atom/instructions/ event can't be enabled on atom PMU
even when the process is pinned on atom core. Investigation shows that
exclusive_event_init() helper always returns -EBUSY error in the perf
event creation. That's strange since the atom PMU should not be an
exclusive PMU.
Further investigation shows the issue was introduced by commit:
97588df87b56 ("perf/x86/intel: Add common intel_pmu_init_hybrid()")
The commit originally intents to clear the bit PERF_PMU_CAP_AUX_OUTPUT
from PMU capabilities if intel_cap.pebs_output_pt_available is not set,
but it incorrectly uses 'or' operation and leads to all PMU capabilities
bits are set to 1 except bit PERF_PMU_CAP_AUX_OUTPUT.
Testing this fix on Intel hybrid platforms, the observed issues
disappear.
Fixes: 97588df87b56 ("perf/x86/intel: Add common intel_pmu_init_hybrid()")
Signed-off-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20231121014628.729989-1-dapeng1.mi@linux.intel.com
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/events/intel/core.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c index a08f794a0e79..ce1c777227b4 100644 --- a/arch/x86/events/intel/core.c +++ b/arch/x86/events/intel/core.c @@ -4660,7 +4660,7 @@ static void intel_pmu_check_hybrid_pmus(struct x86_hybrid_pmu *pmu) if (pmu->intel_cap.pebs_output_pt_available) pmu->pmu.capabilities |= PERF_PMU_CAP_AUX_OUTPUT; else - pmu->pmu.capabilities |= ~PERF_PMU_CAP_AUX_OUTPUT; + pmu->pmu.capabilities &= ~PERF_PMU_CAP_AUX_OUTPUT; intel_pmu_check_event_constraints(pmu->event_constraints, pmu->num_counters, |