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Date:   Sat, 4 Nov 2023 17:01:24 -0400
From:   Sasha Levin <sashal@kernel.org>
To:     Mingwei Zhang <mizhang@google.com>
Cc:     stable@vger.kernel.org, Jim Mattson <jmattson@google.com>,
        Ian Rogers <irogers@google.com>,
        Stephane Eranian <eranian@google.com>
Subject: Re: Request to backport commit f9cdeb58a9cf ("perf evlist: Avoid
 frequency mode for the dummy event") to stable versions of Linux kernel
Message-ID: <ZUaxJDSu2x3RuLx-@sashalap>
References: <CAL715WLTjMGQrhm6wWqFSeL_Oq-HzoQd5CqewvLRLv0Xbnibgw@mail.gmail.com>
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On Wed, Nov 01, 2023 at 12:10:55PM -0700, Mingwei Zhang wrote:
>Hi Greg,
>
>Apology for any inconvenience. This is info and justification for patch.
>
>Commit-id: f9cdeb58a9cf46c09b56f5f661ea8da24b6458c3
>Subject: perf evlist: Avoid frequency mode for the dummy event
>
>Justification:
>
>This patch fixes a critical performance issue at perf-tool level for
>anything running PMU in a virtualized environment.  Majority of the
>justification is within the commit message. The only thing I would
>like to add is that this patch could save up to 50% of the vCPU time
>when running perf in sampling mode with a large number of events in
>the VM.

Queued up, thanks!

-- 
Thanks,
Sasha