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 the process is pinned on atom core. The 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 a exclusive PMU.
Further investigation shows the issue is 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()") Cc: stable@vger.kernel.org Signed-off-by: Dapeng Mi dapeng1.mi@linux.intel.com --- arch/x86/events/intel/core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
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,
base-commit: b85ea95d086471afb4ad062012a4d73cd328fa86