From: Pavel Begunkov <[email protected]>
To: Max Kellermann <[email protected]>,
[email protected], [email protected],
[email protected]
Subject: Re: [PATCH 7/8] io_uring: cache io_kiocb->flags in variable
Date: Wed, 29 Jan 2025 19:11:23 +0000 [thread overview]
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>
On 1/28/25 13:39, Max Kellermann wrote:
> This eliminates several redundant reads, some of which probably cannot
> be optimized away by the compiler.
Let's not, it hurts readability with no clear benefits. In most cases
the compiler will be able to optimise it just where it matters, and
in cold paths we're comparing the overhead of reading a cached variable
with taking locks and doing indirect calls, and even then it'd likely
need to be saved onto the stack and loaded back.
The only place where it might be worth it is io_issue_sqe(), and
even then I'd doubt it.
--
Pavel Begunkov
next prev parent reply other threads:[~2025-01-29 19:11 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-01-28 13:39 [PATCH 0/8] Various io_uring micro-optimizations (reducing lock contention) Max Kellermann
2025-01-28 13:39 ` [PATCH 1/8] io_uring/io-wq: eliminate redundant io_work_get_acct() calls Max Kellermann
2025-01-28 13:39 ` [PATCH 2/8] io_uring/io-wq: add io_worker.acct pointer Max Kellermann
2025-01-28 13:39 ` [PATCH 3/8] io_uring/io-wq: move worker lists to struct io_wq_acct Max Kellermann
2025-01-28 13:39 ` [PATCH 4/8] io_uring/io-wq: cache work->flags in variable Max Kellermann
2025-01-29 18:57 ` Pavel Begunkov
2025-01-29 19:11 ` Max Kellermann
2025-01-29 23:41 ` Pavel Begunkov
2025-01-30 5:36 ` Max Kellermann
2025-01-30 14:57 ` Jens Axboe
2025-01-31 14:06 ` Pavel Begunkov
2025-01-30 14:54 ` Jens Axboe
2025-01-28 13:39 ` [PATCH 5/8] io_uring/io-wq: do not use bogus hash value Max Kellermann
2025-01-28 13:39 ` [PATCH 6/8] io_uring/io-wq: pass io_wq to io_get_next_work() Max Kellermann
2025-01-28 13:39 ` [PATCH 7/8] io_uring: cache io_kiocb->flags in variable Max Kellermann
2025-01-29 19:11 ` Pavel Begunkov [this message]
2025-01-28 13:39 ` [PATCH 8/8] io_uring: skip redundant poll wakeups Max Kellermann
2025-01-31 13:54 ` Pavel Begunkov
2025-01-31 17:16 ` Max Kellermann
2025-01-31 17:25 ` Pavel Begunkov
2025-01-29 17:18 ` [PATCH 0/8] Various io_uring micro-optimizations (reducing lock contention) Jens Axboe
2025-01-29 17:39 ` Max Kellermann
2025-01-29 17:45 ` Jens Axboe
2025-01-29 18:01 ` Max Kellermann
2025-01-31 16:13 ` Jens Axboe
2025-02-01 15:25 ` Jens Axboe
2025-02-01 15:30 ` Max Kellermann
2025-02-01 15:38 ` Jens Axboe
2025-01-29 19:30 ` Pavel Begunkov
2025-01-29 19:43 ` Max Kellermann
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