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

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Message-ID: <20180927125141.GA3439@hirez.programming.kicks-ass.net>
Date:   Thu, 27 Sep 2018 14:51:41 +0200
From:   Peter Zijlstra <peterz@...radead.org>
To:     kan.liang@...ux.intel.com
Cc:     tglx@...utronix.de, mingo@...hat.com, acme@...nel.org,
        linux-kernel@...r.kernel.org, eranian@...gle.com,
        ak@...ux.intel.com, alexander.shishkin@...ux.intel.com
Subject: Re: [PATCH V2 2/3] x86, perf: Add a separate Arch Perfmon v4 PMI
 handler

On Wed, Aug 08, 2018 at 12:12:07AM -0700, kan.liang@...ux.intel.com 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;