From: Jens Axboe <axboe@kernel.dk>
To: io-uring@vger.kernel.org
Cc: changfengnan@bytedance.com, xiaobing.li@samsung.com,
lidiangang@bytedance.com, krisman@suse.de
Subject: [PATCHSET v2 0/2] Fix crazy CPU accounting usage for SQPOLL
Date: Wed, 22 Oct 2025 11:02:46 -0600 [thread overview]
Message-ID: <20251022170416.116554-1-axboe@kernel.dk> (raw)
Hi,
Fengnan Chang reports [1] excessive CPU usage from the SQPOLL work vs
total time accounting, and that indeed does look like a problem. The
issue seems to be just eager time querying, and using essentially the
wrong interface. Patch 1 gets rid of getrusage() for this, and patch 2
attempts to be a bit smarter in how often the time needs to get
queried. Profile results in patch 2 as well.
Since v1:
- Store time in usec rather than convert between nsec and timespec64.
io_uring/fdinfo.c | 8 +++----
io_uring/sqpoll.c | 65 ++++++++++++++++++++++++++++++++++++++-----------------
io_uring/sqpoll.h | 1 +
3 files changed, 50 insertions(+), 24 deletions(-)
--
Jens Axboe
next reply other threads:[~2025-10-22 17:04 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-10-22 17:02 Jens Axboe [this message]
2025-10-22 17:02 ` [PATCH 1/2] io_uring/sqpoll: switch away from getrusage() for CPU accounting Jens Axboe
2025-10-22 17:02 ` [PATCH 2/2] io_uring/sqpoll: be smarter on when to update the stime usage 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=20251022170416.116554-1-axboe@kernel.dk \
--to=axboe@kernel.dk \
--cc=changfengnan@bytedance.com \
--cc=io-uring@vger.kernel.org \
--cc=krisman@suse.de \
--cc=lidiangang@bytedance.com \
--cc=xiaobing.li@samsung.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 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.