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
Date: Sat, 4 Nov 2023 17:01:24 -0400 [thread overview]
Message-ID: <ZUaxJDSu2x3RuLx-@sashalap> (raw)
In-Reply-To: <CAL715WLTjMGQrhm6wWqFSeL_Oq-HzoQd5CqewvLRLv0Xbnibgw@mail.gmail.com>
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
prev parent reply other threads:[~2023-11-04 21:01 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-11-01 19:10 Request to backport commit f9cdeb58a9cf ("perf evlist: Avoid frequency mode for the dummy event") to stable versions of Linux kernel Mingwei Zhang
2023-11-04 21:01 ` Sasha Levin [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=ZUaxJDSu2x3RuLx-@sashalap \
--to=sashal@kernel.org \
--cc=eranian@google.com \
--cc=irogers@google.com \
--cc=jmattson@google.com \
--cc=mizhang@google.com \
--cc=stable@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox