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 2C218C433F5 for ; Mon, 18 Oct 2021 11:34:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0AB1B60E76 for ; Mon, 18 Oct 2021 11:34:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229491AbhJRLgW (ORCPT ); Mon, 18 Oct 2021 07:36:22 -0400 Received: from out30-56.freemail.mail.aliyun.com ([115.124.30.56]:42046 "EHLO out30-56.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229519AbhJRLgV (ORCPT ); Mon, 18 Oct 2021 07:36:21 -0400 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R161e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e04426;MF=haoxu@linux.alibaba.com;NM=1;PH=DS;RN=4;SR=0;TI=SMTPD_---0UsfKpNh_1634556849; Received: from B-25KNML85-0107.local(mailfrom:haoxu@linux.alibaba.com fp:SMTPD_---0UsfKpNh_1634556849) by smtp.aliyun-inc.com(127.0.0.1); Mon, 18 Oct 2021 19:34:09 +0800 Subject: Re: [PATCH 2/2] 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: <20211018112923.16874-1-haoxu@linux.alibaba.com> <20211018112923.16874-3-haoxu@linux.alibaba.com> Message-ID: <07ecb722-bf42-b785-2064-79221a3362cc@linux.alibaba.com> Date: Mon, 18 Oct 2021 19:34:08 +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: <20211018112923.16874-3-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 在 2021/10/18 下午7:29, 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 An irrelevant question: why do we do linked timeout logic in io_wq_submit_work() again regarding that we've already done it in io_queue_async_work().