Re: [PATCH v2 1/3] KVM: x86/pmu: Make part of the Intel v2 PMU MSRs handling x86 generic

From: Sean Christopherson
Date: Thu Oct 27 2022 - 18:14:21 EST


On Thu, Sep 22, 2022, Like Xu wrote:
> Subject: [PATCH] KVM: x86/pmu: Rewrite reprogram_counters() to improve
> performance
>
> Before using pmu->reprogram_pmi, the test for a valid pmc is always
> applied. This part of the redundancy could be removed by setting the
> counters' bitmask directly, and furthermore triggering KVM_REQ_PMU
> only once to save more cycles.

Assuming you plan on posting this, please explicitly state what the patch does.
"This part of the redundancy could" only says what _could_ be done, not what is
actually done. Oftentimes, a changelog will say something "could" be done when
talking about alternative solutions. So when I see "could", I think "this is
what the patch _isn't_ doing".