linux-kernel - Re: [PATCH v2 8/9] perf/x86/intel: Shadow MSR_ARCH_PERFMON_FIXED_CTR

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Date:   Thu, 1 Sep 2022 11:10:49 +0200
From:   Peter Zijlstra <peterz@...radead.org>
To:     "Liang, Kan" <kan.liang@...ux.intel.com>
Cc:     x86@...nel.org, eranian@...gle.com, ravi.bangoria@....com,
        linux-kernel@...r.kernel.org, acme@...nel.org,
        mark.rutland@....com, alexander.shishkin@...ux.intel.com,
        jolsa@...nel.org, namhyung@...nel.org
Subject: Re: [PATCH v2 8/9] perf/x86/intel: Shadow
 MSR_ARCH_PERFMON_FIXED_CTR_CTRL

On Wed, Aug 31, 2022 at 09:52:19AM -0400, Liang, Kan wrote:
> 
> 
> On 2022-08-29 6:10 a.m., Peter Zijlstra wrote:
> > Less RDMSR is more better.
> 
> I had an RFC patch which does a further step to move the fixed
> control register write to right before the entire PMU re-enabling, which
> could also save some writes if there are several fixed counters enabled.
> https://lore.kernel.org/lkml/20220804140729.2951259-1-kan.liang@linux.intel.com/
> 
> Do you have any comments for the RFC patch?
> 

Oh, I like that better, let me just replace my patch with that.