From: Shakeel Butt <shakeelb@google.com>
To: Ivan Babrou <ivan@cloudflare.com>
Cc: "Daniel Dao" <dqminh@cloudflare.com>,
kernel-team <kernel-team@cloudflare.com>,
"Linux MM" <linux-mm@kvack.org>,
"Johannes Weiner" <hannes@cmpxchg.org>,
"Roman Gushchin" <guro@fb.com>, "Feng Tang" <feng.tang@intel.com>,
"Michal Hocko" <mhocko@kernel.org>,
"Hillf Danton" <hdanton@sina.com>,
"Michal Koutný" <mkoutny@suse.com>,
"Andrew Morton" <akpm@linux-foundation.org>,
"Linus Torvalds" <torvalds@linux-foundation.org>
Subject: Re: Regression in workingset_refault latency on 5.15
Date: Fri, 25 Feb 2022 09:22:20 -0800 [thread overview]
Message-ID: <CALvZod7_C0EXQQ0cibeQw3_G32KH0w7cWY7eigQyTLZLeoec9Q@mail.gmail.com> (raw)
In-Reply-To: <CABWYdi0=_c0VLSBj7RN+Hu9E2FwenqpF-PdLwzp1aWq0fwtmBw@mail.gmail.com>
On Fri, Feb 25, 2022 at 9:09 AM Ivan Babrou <ivan@cloudflare.com> wrote:
>
> On Fri, Feb 25, 2022 at 2:23 AM Daniel Dao <dqminh@cloudflare.com> wrote:
> > I think this looks good so far.
>
> I compared a flamegraph before to a flamegraph after (10s @ 99Hz on
> 96-core CPU evenly loaded to ~75% in both cases).
>
> Before: 1.4% spent in workingset_refault.
> After: 0.5% spent in flush_memcg_stats_dwork.
>
> The latter is all in kworkers (as expected), while the former is
> spread across IO active tasks.
>
> This seems like a great first step that should be merged on its own.
> It would be good to also do something to improve the CPU time spent in
> delayed work, if possible, as 0.5% of on-CPU time is not a negligible
> amount.
I will send the official async patch soon and I agree that we need to
improve rstat flush infrastructure as well but that would need more
thought and time.
next prev parent reply other threads:[~2022-02-25 17:22 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-23 13:51 Daniel Dao
2022-02-23 15:57 ` Shakeel Butt
2022-02-23 16:00 ` Shakeel Butt
2022-02-23 17:07 ` Daniel Dao
2022-02-23 17:36 ` Shakeel Butt
2022-02-23 19:28 ` Ivan Babrou
2022-02-23 20:28 ` Shakeel Butt
2022-02-23 21:16 ` Ivan Babrou
2022-02-24 14:46 ` Daniel Dao
2022-02-24 16:58 ` Shakeel Butt
2022-02-24 17:34 ` Daniel Dao
2022-02-24 18:00 ` Shakeel Butt
2022-02-24 18:52 ` Shakeel Butt
2022-02-25 10:23 ` Daniel Dao
2022-02-25 17:08 ` Ivan Babrou
2022-02-25 17:22 ` Shakeel Butt [this message]
2022-02-25 18:03 ` Michal Koutný
2022-02-25 18:08 ` Ivan Babrou
2022-02-28 23:09 ` Shakeel Butt
2022-02-28 23:34 ` Ivan Babrou
2022-02-28 23:43 ` Shakeel Butt
2022-03-02 0:48 ` Ivan Babrou
2022-03-02 2:50 ` Shakeel Butt
2022-03-02 3:40 ` Ivan Babrou
2022-03-02 22:33 ` Ivan Babrou
2022-03-03 2:32 ` Shakeel Butt
2022-03-03 2:35 ` Shakeel Butt
2022-03-04 0:21 ` Ivan Babrou
2022-03-04 1:05 ` Shakeel Butt
2022-03-04 1:12 ` Ivan Babrou
2022-03-02 11:49 ` Frank Hofmann
2022-03-02 15:52 ` Shakeel Butt
2022-03-02 10:08 ` Michal Koutný
2022-03-02 15:53 ` Shakeel Butt
2022-03-02 17:28 ` Ivan Babrou
2022-02-24 9:22 ` Thorsten Leemhuis
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