Re: [PATCH V2 2/3] x86, perf: Add a separate Arch Perfmon v4 PMI handler

[Peter Zijlstra]

On Wed, Aug 08, 2018 at 12:12:07AM -0700, kan.liang@xxxxxxxxxxxxxxx wrote:
> @@ -4325,6 +4428,8 @@ __init int intel_pmu_init(void)
>  		x86_pmu.extra_regs = intel_skl_extra_regs;
>  		x86_pmu.pebs_aliases = intel_pebs_aliases_skl;
>  		x86_pmu.pebs_prec_dist = true;
> +		x86_pmu.counter_freezing = disable_counter_freezing ?
> +					   false : true;
>  		/* all extra regs are per-cpu when HT is on */
>  		x86_pmu.flags |= PMU_FL_HAS_RSP_1;
>  		x86_pmu.flags |= PMU_FL_NO_HT_SHARING;


How about so instead? It is very much tied to the perfmon version, not
the FMS.

--- a/arch/x86/events/intel/core.c
+++ b/arch/x86/events/intel/core.c
@@ -4049,6 +4049,9 @@ __init int intel_pmu_init(void)
 			max((int)edx.split.num_counters_fixed, assume);
 	}
 
+	if (version >= 4)
+		x86_pmu.counter_freezing = !disable_counter_freezing;
+
 	if (boot_cpu_has(X86_FEATURE_PDCM)) {
 		u64 capabilities;
 
@@ -4428,8 +4431,6 @@ __init int intel_pmu_init(void)
 		x86_pmu.extra_regs = intel_skl_extra_regs;
 		x86_pmu.pebs_aliases = intel_pebs_aliases_skl;
 		x86_pmu.pebs_prec_dist = true;
-		x86_pmu.counter_freezing = disable_counter_freezing ?
-					   false : true;
 		/* all extra regs are per-cpu when HT is on */
 		x86_pmu.flags |= PMU_FL_HAS_RSP_1;
 		x86_pmu.flags |= PMU_FL_NO_HT_SHARING;