From: Phil Elwell <[email protected]>
To: [email protected]
Cc: [email protected], [email protected], [email protected],
[email protected], [email protected],
LKML <[email protected]>,
[email protected], stable <[email protected]>
Subject: Re: [PATCH] io_uring: Use io_schedule* in cqring wait
Date: Mon, 24 Jul 2023 16:35:43 +0100 [thread overview]
Message-ID: <CAMEGJJ2RxopfNQ7GNLhr7X9=bHXKo+G5OOe0LUq=+UgLXsv1Xg@mail.gmail.com> (raw)
Hi Andres,
With this commit applied to the 6.1 and later kernels (others not
tested) the iowait time ("wa" field in top) in an ARM64 build running
on a 4 core CPU (a Raspberry Pi 4 B) increases to 25%, as if one core
is permanently blocked on I/O. The change can be observed after
installing mariadb-server (no configuration or use is required). After
reverting just this commit, "wa" drops to zero again.
I can believe that this change hasn't negatively affected performance,
but the result is misleading. I also think it's pushing the boundaries
of what a back-port to stable should do.
Phil
next reply other threads:[~2023-07-24 15:35 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-07-24 15:35 Phil Elwell [this message]
2023-07-24 15:48 ` [PATCH] io_uring: Use io_schedule* in cqring wait Greg KH
2023-07-24 15:50 ` Jens Axboe
2023-07-24 15:58 ` Jens Axboe
2023-07-24 16:07 ` Phil Elwell
2023-07-24 16:08 ` Jens Axboe
2023-07-24 16:48 ` Phil Elwell
2023-07-24 18:22 ` Jens Axboe
2023-07-24 19:22 ` Pavel Begunkov
2023-07-24 20:27 ` Jeff Moyer
2023-07-24 15:48 ` Jens Axboe
2023-07-24 16:16 ` Andres Freund
2023-07-24 16:20 ` Jens Axboe
2023-07-24 17:24 ` Andres Freund
2023-07-24 17:44 ` Jens Axboe
-- strict thread matches above, loose matches on Subject: below --
2023-07-18 19:49 [PATCHSET v2 0/5] Improve async iomap DIO performance Jens Axboe
2023-07-18 19:49 ` [PATCH] io_uring: Use io_schedule* in cqring wait Jens Axboe
2023-07-18 19:50 ` Jens Axboe
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='CAMEGJJ2RxopfNQ7GNLhr7X9=bHXKo+G5OOe0LUq=+UgLXsv1Xg@mail.gmail.com' \
[email protected] \
[email protected] \
[email protected] \
[email protected] \
[email protected] \
[email protected] \
[email protected] \
[email protected] \
[email protected] \
[email protected] \
/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