From: Jens Axboe <[email protected]>
To: Pavel Begunkov <[email protected]>, [email protected]
Subject: Re: [PATCH v2 0/5] skip request refcounting
Date: Wed, 11 Aug 2021 18:34:57 -0600 [thread overview]
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>
On 8/11/21 12:28 PM, Pavel Begunkov wrote:
> With some tricks, we can avoid refcounting in most of the cases and
> so save on atomics. 1-2 are simple preparations and 3-4 are the meat.
> 5/5 is a hint to the compiler, which stopped to similarly optimise it
> as is.
>
> Jens tried out a prototype before, apparently it gave ~3% win for
> the default read test. Not much has changed since then, so I'd
> expect same result, and also hope that it should be of even greater
> benefit to multithreaded workloads.
>
> The previous version had a flaw, so it was decided to move all
> completions out of IRQ and base on that assumption. On top of
> io_uring-irq branch.
This is really nice, both in terms of how the series is laid out,
but also the reasoning behind it. I can't shoot any immediate holes
in it, let's get it queued for 5.15.
--
Jens Axboe
prev parent reply other threads:[~2021-08-12 0:35 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-11 18:28 [PATCH v2 0/5] skip request refcounting Pavel Begunkov
2021-08-11 18:28 ` [PATCH v2 1/5] io_uring: move req_ref_get() and friends Pavel Begunkov
2021-08-11 18:28 ` [PATCH v2 2/5] io_uring: remove req_ref_sub_and_test() Pavel Begunkov
2021-08-11 18:28 ` [PATCH v2 3/5] io_uring: remove submission references Pavel Begunkov
2021-08-11 18:28 ` [PATCH v2 4/5] io_uring: skip request refcounting Pavel Begunkov
2021-08-11 18:28 ` [PATCH v2 5/5] io_uring: optimise hot path of ltimeout prep Pavel Begunkov
2021-08-12 0:34 ` Jens Axboe [this message]
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