Earlier workaround added by commit 400816f60c54 ("perf/x86/intel:
Implement support for TSX Force Abort") for perf counter interactions
[1] are not required on some client systems which received a microcode
update that deprecates TSX.
Bypass the perf workaround when such microcode is enumerated.
[1] Performance Monitoring Impact of Intel® Transactional Synchronization Extension Memory
http://cdrdv2.intel.com/v1/dl/getContent/604224 (Document ID 604224)
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@xxxxxxxxxxxxxxx>
Reviewed-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Reviewed-by: Tony Luck <tony.luck@xxxxxxxxx>
Tested-by: Neelima Krishnan <neelima.krishnan@xxxxxxxxx>
---
arch/x86/events/intel/core.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)
diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c
index e28892270c58..b599a30fcc7d 100644
--- a/arch/x86/events/intel/core.c
+++ b/arch/x86/events/intel/core.c
@@ -6015,7 +6015,15 @@ __init int intel_pmu_init(void)
tsx_attr = hsw_tsx_events_attrs;
intel_pmu_pebs_data_source_skl(pmem);
- if (boot_cpu_has(X86_FEATURE_TSX_FORCE_ABORT)) {
+ /* Processors with CPUID.RTM_ALWAYS_ABORT have TSX deprecated by
+ * default. TSX force abort hooks are not required on these
+ * systems.
+ *
+ * Only deploy the workaround when older microcode is detected
+ * i.e. !X86_FEATURE_RTM_ALWAYS_ABORT.
+ */
+ if (boot_cpu_has(X86_FEATURE_TSX_FORCE_ABORT) &&
+ !boot_cpu_has(X86_FEATURE_RTM_ALWAYS_ABORT)) {
x86_pmu.flags |= PMU_FL_TFA;
x86_pmu.get_event_constraints = tfa_get_event_constraints;
x86_pmu.enable_all = intel_tfa_pmu_enable_all;
--
git-series 0.9.1
