From: Valentin Schneider <valentin.schneider@arm.com>
To: Meelis Roos <mroos@linux.ee>, LKML <linux-kernel@vger.kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>,
Vincent Guittot <vincent.guittot@linaro.org>,
Barry Song <song.bao.hua@hisilicon.com>,
Mel Gorman <mgorman@suse.de>,
Dietmar Eggemann <dietmar.eggemann@arm.com>
Subject: Re: 5.11-rc4+git: Shortest NUMA path spans too many nodes
Date: Thu, 21 Jan 2021 15:05:32 +0000 [thread overview]
Message-ID: <jhjmtx22uv7.mognet@arm.com> (raw)
In-Reply-To: <3ec17983-7959-eccd-af25-400056a5877d@linux.ee>
(+Cc relevant folks)
Hi,
On 21/01/21 15:41, Meelis Roos wrote:
> This happens on Sun Fire X4600 M2 - 32 cores in 8 CPU slots. 5.10 was silent. Current git and
> 5.10.0-13256-g5814bc2d4cc2 exhibit this message in dmesg but otherwise seem to work fine
> (kernel compilation succeeds).
>
b5b217346de8 ("sched/topology: Warn when NUMA diameter > 2") was added in
5.11-rc1, and I believe was marked for stable.
It doesn't come with a scheduler behaviour change, it only catches
topologies that end up being silently (unless run with SCHED_DEBUG=y)
misrepresented / misinterpreted by the scheduler.
Up until now I had only seen it fire on a single, somewhat unusual
topology. As fixing it is far from trivial, I figured adding this warning
would let us build a case for actually fixing it if we get some more
reports.
Could you paste the output of the below?
$ cat /sys/devices/system/node/node*/distance
Additionally, booting your system with CONFIG_SCHED_DEBUG=y and
appending 'sched_debug' to your cmdline should yield some extra data.
next prev parent reply other threads:[~2021-01-21 15:09 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-21 13:41 5.11-rc4+git: Shortest NUMA path spans too many nodes Meelis Roos
2021-01-21 15:05 ` Valentin Schneider [this message]
2021-01-21 17:39 ` Meelis Roos
2021-01-21 18:21 ` Valentin Schneider
2021-01-21 18:53 ` Dietmar Eggemann
2021-01-21 21:17 ` Song Bao Hua (Barry Song)
2021-01-22 10:05 ` Dietmar Eggemann
2021-01-22 11:09 ` Song Bao Hua (Barry Song)
2021-01-22 11:16 ` Valentin Schneider
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=jhjmtx22uv7.mognet@arm.com \
--to=valentin.schneider@arm.com \
--cc=dietmar.eggemann@arm.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mgorman@suse.de \
--cc=mroos@linux.ee \
--cc=peterz@infradead.org \
--cc=song.bao.hua@hisilicon.com \
--cc=vincent.guittot@linaro.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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.