From: "Carter Li 李通洲" <carter.li@eoitek.com>
To: Jens Axboe <axboe@kernel.dk>
Cc: Peter Zijlstra <peterz@infradead.org>,
Pavel Begunkov <asml.silence@gmail.com>,
io-uring <io-uring@vger.kernel.org>
Subject: Re: [ISSUE] The time cost of IOSQE_IO_LINK
Date: Sat, 15 Feb 2020 01:25:58 +0000
Message-ID: <72423161-38EF-49D1-8229-18C328AB5DA1@eoitek.com> (raw)
In-Reply-To: <f1610a65-0bf9-8134-3e8d-72cccd2f5468@kernel.dk>
There are at least 2 benefits over POLL->READ
1. Reduce a little complexity of user code, and save lots of sqes.
2. Better performance. Users can’t if an operation will block without
issuing an extra O_NONBLOCK syscall, which ends up with always using
POLL->READ link. If it’s handled by kernel, we may only poll when
we know it’s needed.
> 2020年2月15日 上午9:10，Jens Axboe <axboe@kernel.dk> 写道：
>
> On 2/14/20 5:16 PM, Carter Li 李通洲 wrote:
>> Hello Jens,
>>
>>
>>> It's now up to 3.5x the original performance for the single client case.
>>> Here's the updated patch, folded with the original that only went half
>>> the way there.
>>
>>
>> I’m looking forward to it.
>>
>> And question again: since POLL->READ/RECV is much faster then READ/RECV async,
>> could we implement READ/RECV that would block as POLL->READ/RECV? Not only for
>> networking, but also for all pollable fds.
>
> That's exactly the next step. With this, we have a very efficient way of
> doing async IO for anything that can be driven by poll. Then we can do it
> by default, instead of doing an async punt. Much faster and much more
> efficient.
>
> I'll try and work on that next week, I think this could be a real game
> changer.
>
> --
> Jens Axboe
next prev parent reply index
Thread overview: 53+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-12 16:31 Carter Li 李通洲
2020-02-12 17:11 ` Jens Axboe
2020-02-12 17:22 ` Jens Axboe
2020-02-12 17:29 ` Jens Axboe
2020-02-13 0:33 ` Carter Li 李通洲
2020-02-13 15:08 ` Pavel Begunkov
2020-02-13 15:14 ` Jens Axboe
2020-02-13 15:51 ` Carter Li 李通洲
2020-02-14 1:25 ` Carter Li 李通洲
2020-02-14 2:45 ` Jens Axboe
2020-02-14 5:03 ` Jens Axboe
2020-02-14 15:32 ` Peter Zijlstra
2020-02-14 15:47 ` Jens Axboe
2020-02-14 16:18 ` Jens Axboe
2020-02-14 17:52 ` Jens Axboe
2020-02-14 20:44 ` Jens Axboe
2020-02-15 0:16 ` Carter Li 李通洲
2020-02-15 1:10 ` Jens Axboe
2020-02-15 1:25 ` Carter Li 李通洲 [this message]
2020-02-15 1:27 ` Jens Axboe
2020-02-15 6:01 ` Jens Axboe
2020-02-15 6:32 ` Carter Li 李通洲
2020-02-15 15:11 ` Jens Axboe
2020-02-16 19:06 ` Pavel Begunkov
2020-02-16 22:23 ` Jens Axboe
2020-02-17 10:30 ` Pavel Begunkov
2020-02-17 19:30 ` Jens Axboe
2020-02-16 23:06 ` Jens Axboe
2020-02-16 23:07 ` Jens Axboe
2020-02-17 12:09 ` Peter Zijlstra
2020-02-17 16:12 ` Jens Axboe
2020-02-17 17:16 ` Jens Axboe
2020-02-17 17:46 ` Peter Zijlstra
2020-02-17 18:16 ` Jens Axboe
2020-02-18 13:13 ` Peter Zijlstra
2020-02-18 14:27 ` [PATCH] asm-generic/atomic: Add try_cmpxchg() fallbacks Peter Zijlstra
2020-02-18 14:40 ` Peter Zijlstra
2020-02-20 10:30 ` Will Deacon
2020-02-20 10:37 ` Peter Zijlstra
2020-02-20 10:39 ` Will Deacon
2020-02-18 14:56 ` [ISSUE] The time cost of IOSQE_IO_LINK Oleg Nesterov
2020-02-18 15:07 ` Oleg Nesterov
2020-02-18 15:38 ` Peter Zijlstra
2020-02-18 16:33 ` Jens Axboe
2020-02-18 15:07 ` Peter Zijlstra
2020-02-18 15:50 ` [PATCH] task_work_run: don't take ->pi_lock unconditionally Oleg Nesterov
2020-02-20 16:39 ` Peter Zijlstra
2020-02-20 17:22 ` Oleg Nesterov
2020-02-20 17:49 ` Peter Zijlstra
2020-02-21 14:52 ` Oleg Nesterov
2020-02-18 16:46 ` [ISSUE] The time cost of IOSQE_IO_LINK Jens Axboe
2020-02-18 16:52 ` Jens Axboe
2020-02-18 13:13 ` Peter Zijlstra
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