From: Jens Axboe <axboe@kernel.dk>
To: qemu-block@nongnu.org
Cc: qemu-devel@nongnu.org, fam@euphon.net, stefanha@redhat.com
Subject: [PATCHSET 0/2] io_uring fixes
Date: Fri, 13 Feb 2026 07:26:35 -0700 [thread overview]
Message-ID: <20260213143225.161043-1-axboe@kernel.dk> (raw)
Hi,
Patch 1 here is the real meat of this, patch 2 is just a slight
improvement. For patch 1, it can literally yield a 50-80x improvement
on the io_uring side for idle systems, where ppoll() ends up sleeping
for 500 msec while there's IO to submit! I noticed this running the
io_uring regression tests in a vm, where I use a variety of block
devices for some of the tests. They would often randomly time out on
AHCI devices, while running them on a virtio-blk or nvme device would
finish in one second or so. I then wrote a reproducer to try and grok
this and had claude dive into this, which helped me better grasp the
various event loops.
Please take a look and tell me what you think. Some variant of patch 1
should definitely be considered, but let me know if this is the right
approach. I can easily test anything.
Also note - this seems to trigger more easily or consistently on
aarch64, which is where I run most of my local/immediate testing.
util/fdmon-io_uring.c | 22 +++++++++++++++++++++-
1 file changed, 21 insertions(+), 1 deletion(-)
--
Jens Axboe
next reply other threads:[~2026-02-13 14:33 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-02-13 14:26 Jens Axboe [this message]
2026-02-13 14:26 ` [PATCH 1/2] fdmon-io_uring: notify main loop when SQEs are queued Jens Axboe
2026-02-13 16:04 ` Kevin Wolf
2026-02-18 9:57 ` Fiona Ebner
2026-02-18 16:06 ` Stefan Hajnoczi
2026-02-18 16:17 ` Jens Axboe
2026-02-18 20:02 ` Stefan Hajnoczi
2026-02-18 16:11 ` Stefan Hajnoczi
2026-02-18 16:19 ` Jens Axboe
2026-02-18 16:41 ` [PATCH v2] aio-posix: " Jens Axboe
2026-02-18 20:57 ` Stefan Hajnoczi
2026-02-19 14:27 ` Jens Axboe
2026-02-19 15:49 ` Kevin Wolf
2026-02-23 13:53 ` Stefan Hajnoczi
2026-02-18 15:56 ` [PATCH 1/2] fdmon-io_uring: " Stefan Hajnoczi
2026-02-13 14:26 ` [PATCH 2/2] fdmon-io_uring: check CQ ring directly in gsource_check Jens Axboe
2026-02-13 16:22 ` Kevin Wolf
2026-02-18 16:24 ` Stefan Hajnoczi
2026-02-18 10:07 ` [PATCHSET 0/2] io_uring fixes Fiona Ebner
2026-03-03 11:52 ` Fiona Ebner
2026-03-03 16:51 ` Jens Axboe
2026-03-08 12:11 ` Michael Tokarev
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