From: "gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>
To: Vincent Guittot <vincent.guittot@linaro.org>
Cc: Vishnu Rangayyan <vishnu.rangayyan@apple.com>,
Sasha Levin <sashal@kernel.org>,
"# v4 . 16+" <stable@vger.kernel.org>,
Andrew Forgue <andrewf@apple.com>,
Peter Zijlstra <peterz@infradead.org>,
Dietmar Eggemann <dietmar.eggemann@arm.com>,
"Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
Subject: Re: Fixes for 4.19 stable
Date: Tue, 3 Mar 2020 16:43:30 +0100 [thread overview]
Message-ID: <20200303154330.GA372992@kroah.com> (raw)
In-Reply-To: <CAKfTPtAHpJmEXzBtaeFA+PHDEzZq+0DfG+LABcTRnXCVz=6adQ@mail.gmail.com>
On Tue, Mar 03, 2020 at 09:03:15AM +0100, Vincent Guittot wrote:
> On Tue, 3 Mar 2020 at 00:13, Vishnu Rangayyan
> <vishnu.rangayyan@apple.com> wrote:
> >
> > Hi Sasha,
> >
> > Not sure of this, looks relevant but I'm no expert on this code.
> > This particular change bef69dd87828 doesn't apply cleanly, need to
> > backport it. I'll do that now and retest on the failing setup and report
> > back.
> >
> > Best
> > Vishnu
> >
> > On 2/29/20 7:11 PM, Sasha Levin wrote:
> > > On Fri, Feb 28, 2020 at 12:13:54PM -0800, Vishnu Rangayyan wrote:
> > >> Hi,
> > >>
> > >> I still see high (upto 30%) ksoftirqd cpu use with 4.19.101+ after
> > >> these 2 back ports went in for 4.19.101
> > >> (had all 4 backports applied earlier to our tree):
> > >>
> > >> commit f6783319737f28e4436a69611853a5a098cbe974 sched/fair: Fix
> > >> insertion in rq->leaf_cfs_rq_list
> > >> commit 5d299eabea5a251fbf66e8277704b874bbba92dc sched/fair: Add
> > >> tmp_alone_branch assertion
> > >>
> > >> perf shows for any given ksoftirqd, with 20k-30k processes on the
> > >> system with high scheduler load:
> > >> 58.88% ksoftirqd/0 [kernel.kallsyms] [k] update_blocked_averages
> > >>
> > >> Can we backport these 2 also, confirmed that it fixes this behavior of
> > >> ksoftirqd.
> > >>
> > >> commit 039ae8bcf7a5f4476f4487e6bf816885fb3fb617 upstream
> > >> commit 31bc6aeaab1d1de8959b67edbed5c7a4b3cdbe7c upstream
> > >
> > > Do we also need bef69dd87828 ("sched/cpufreq: Move the
> > > cfs_rq_util_change() call to cpufreq_update_util()") then?
>
> This patch is not related to the 2 patches above. It removes some
> spurious call to cfs_rq_util_change() and some wrong ordering but this
> is a fixed overhead which is not impacted by the number of cgroups
> unlike the 2 patches above. This patch will not help with the high
> load of update_blocked_averages
Thanks for letting us know, the other two patches are now queued up.
greg k-h
prev parent reply other threads:[~2020-03-03 15:43 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-28 20:13 Fixes for 4.19 stable Vishnu Rangayyan
2020-03-01 3:11 ` Sasha Levin
2020-03-02 23:13 ` Vishnu Rangayyan
2020-03-03 8:03 ` Vincent Guittot
2020-03-03 15:43 ` gregkh [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=20200303154330.GA372992@kroah.com \
--to=gregkh@linuxfoundation.org \
--cc=andrewf@apple.com \
--cc=dietmar.eggemann@arm.com \
--cc=peterz@infradead.org \
--cc=rafael.j.wysocki@intel.com \
--cc=sashal@kernel.org \
--cc=stable@vger.kernel.org \
--cc=vincent.guittot@linaro.org \
--cc=vishnu.rangayyan@apple.com \
/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