From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 56861C433EF for ; Fri, 22 Oct 2021 03:43:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 32EC261A0C for ; Fri, 22 Oct 2021 03:43:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232868AbhJVDqD (ORCPT ); Thu, 21 Oct 2021 23:46:03 -0400 Received: from out30-133.freemail.mail.aliyun.com ([115.124.30.133]:49476 "EHLO out30-133.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232859AbhJVDqC (ORCPT ); Thu, 21 Oct 2021 23:46:02 -0400 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R151e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e04423;MF=haoxu@linux.alibaba.com;NM=1;PH=DS;RN=4;SR=0;TI=SMTPD_---0UtDN3YM_1634874223; Received: from B-25KNML85-0107.local(mailfrom:haoxu@linux.alibaba.com fp:SMTPD_---0UtDN3YM_1634874223) by smtp.aliyun-inc.com(127.0.0.1); Fri, 22 Oct 2021 11:43:44 +0800 Subject: Re: [PATCH v3] io_uring: implement async hybrid mode for pollable requests From: Hao Xu To: Jens Axboe Cc: io-uring@vger.kernel.org, Pavel Begunkov , Joseph Qi References: <20211018133445.103438-1-haoxu@linux.alibaba.com> Message-ID: <22cc3825-7378-3e30-b3da-36fc0512c2be@linux.alibaba.com> Date: Fri, 22 Oct 2021 11:43:43 +0800 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:78.0) Gecko/20100101 Thunderbird/78.13.0 MIME-Version: 1.0 In-Reply-To: <20211018133445.103438-1-haoxu@linux.alibaba.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org ping this one.. 在 2021/10/18 下午9:34, Hao Xu 写道: > The current logic of requests with IOSQE_ASYNC is first queueing it to > io-worker, then execute it in a synchronous way. For unbound works like > pollable requests(e.g. read/write a socketfd), the io-worker may stuck > there waiting for events for a long time. And thus other works wait in > the list for a long time too. > Let's introduce a new way for unbound works (currently pollable > requests), with this a request will first be queued to io-worker, then > executed in a nonblock try rather than a synchronous way. Failure of > that leads it to arm poll stuff and then the worker can begin to handle > other works. > The detail process of this kind of requests is: > > step1: original context: > queue it to io-worker > step2: io-worker context: > nonblock try(the old logic is a synchronous try here) > | > |--fail--> arm poll > | > |--(fail/ready)-->synchronous issue > | > |--(succeed)-->worker finish it's job, tw > take over the req > > This works much better than the old IOSQE_ASYNC logic in cases where > unbound max_worker is relatively small. In this case, number of > io-worker eazily increments to max_worker, new worker cannot be created > and running workers stuck there handling old works in IOSQE_ASYNC mode. > > In my 64-core machine, set unbound max_worker to 20, run echo-server, > turns out: > (arguments: register_file, connetion number is 1000, message size is 12 > Byte) > original IOSQE_ASYNC: 76664.151 tps > after this patch: 166934.985 tps > > Suggested-by: Jens Axboe > Signed-off-by: Hao Xu > --- > > v1-->v2: > - tweak added code in io_wq_submit_work to reduce overhead > v2-->v3: > - remove redundant IOSQE_ASYNC_HYBRID stuff > > > fs/io_uring.c | 36 +++++++++++++++++++++++++++++++++++- > 1 file changed, 35 insertions(+), 1 deletion(-) > > diff --git a/fs/io_uring.c b/fs/io_uring.c > index b3546eef0289..86819c7917df 100644 > --- a/fs/io_uring.c > +++ b/fs/io_uring.c > @@ -6747,8 +6747,18 @@ static void io_wq_submit_work(struct io_wq_work *work) > ret = -ECANCELED; > > if (!ret) { > + bool needs_poll = false; > + unsigned int issue_flags = IO_URING_F_UNLOCKED; > + > + if (req->flags & REQ_F_FORCE_ASYNC) { > + needs_poll = req->file && file_can_poll(req->file); > + if (needs_poll) > + issue_flags |= IO_URING_F_NONBLOCK; > + } > + > do { > - ret = io_issue_sqe(req, IO_URING_F_UNLOCKED); > +issue_sqe: > + ret = io_issue_sqe(req, issue_flags); > /* > * We can get EAGAIN for polled IO even though we're > * forcing a sync submission from here, since we can't > @@ -6756,6 +6766,30 @@ static void io_wq_submit_work(struct io_wq_work *work) > */ > if (ret != -EAGAIN) > break; > + if (needs_poll) { > + bool armed = false; > + > + ret = 0; > + needs_poll = false; > + issue_flags &= ~IO_URING_F_NONBLOCK; > + > + switch (io_arm_poll_handler(req)) { > + case IO_APOLL_READY: > + goto issue_sqe; > + case IO_APOLL_ABORTED: > + /* > + * somehow we failed to arm the poll infra, > + * fallback it to a normal async worker try. > + */ > + break; > + case IO_APOLL_OK: > + armed = true; > + break; > + } > + > + if (armed) > + break; > + } > cond_resched(); > } while (1); > } >