From: Pavel Begunkov <asml.silence@gmail.com>
To: Fengnan Chang <changfengnan@bytedance.com>,
axboe@kernel.dk, xiaobing.li@samsung.com,
io-uring@vger.kernel.org
Cc: Diangang Li <lidiangang@bytedance.com>
Subject: Re: [PATCH] io_uring: add IORING_SETUP_NO_SQTHREAD_STATS flag to disable sqthread stats collection
Date: Thu, 16 Oct 2025 13:04:35 +0100 [thread overview]
Message-ID: <28a8fdc0-2693-4ff1-bcb3-2b8f67e7b794@gmail.com> (raw)
In-Reply-To: <20251016114519.57780-1-changfengnan@bytedance.com>
On 10/16/25 12:45, Fengnan Chang wrote:
> introduces a new flag IORING_SETUP_NO_SQTHREAD_STATS that allows
> user to disable the collection of statistics in the sqthread.
> When this flag is set, the getrusage() calls in the sqthread are
> skipped, which can provide a small performance improvement in high
> IOPS workloads.
It was added for dynamically adjusting SQPOLL timeouts, at least that
what the author said, but then there is only the fdinfo to access it,
which is slow and unreliable, and no follow up to expose it in a
better way. To be honest, I have serious doubts it has ever been used,
and I'd be tempted to completely remove it out of the kernel. Fdinfo
format wasn't really stable for io_uring and we can leave it printing
some made up values like 100% util.
If it's there for outside monitoring, that should be done with bpf,
with maybe additional tracepoints.
--
Pavel Begunkov
next prev parent reply other threads:[~2025-10-16 12:03 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-10-16 11:45 [PATCH] io_uring: add IORING_SETUP_NO_SQTHREAD_STATS flag to disable sqthread stats collection Fengnan Chang
2025-10-16 12:04 ` Pavel Begunkov [this message]
2025-10-16 12:09 ` [External] " Fengnan Chang
[not found] ` <CGME20251017091046epcas5p35dfbcf4979f79b3a80441aed2d31a906@epcas5p3.samsung.com>
2025-10-17 9:06 ` Xiaobing Li
2025-10-17 9:21 ` [External] " Fengnan Chang
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