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 X-Spam-Level: X-Spam-Status: No, score=-12.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,MAILING_LIST_MULTI, NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8AB54C4338F for ; Mon, 23 Aug 2021 18:41:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6196E611C9 for ; Mon, 23 Aug 2021 18:41:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229962AbhHWSmD (ORCPT ); Mon, 23 Aug 2021 14:42:03 -0400 Received: from out30-57.freemail.mail.aliyun.com ([115.124.30.57]:42754 "EHLO out30-57.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229883AbhHWSmD (ORCPT ); Mon, 23 Aug 2021 14:42:03 -0400 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R411e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e04395;MF=haoxu@linux.alibaba.com;NM=1;PH=DS;RN=4;SR=0;TI=SMTPD_---0UlQlpAX_1629744078; Received: from B-25KNML85-0107.local(mailfrom:haoxu@linux.alibaba.com fp:SMTPD_---0UlQlpAX_1629744078) by smtp.aliyun-inc.com(127.0.0.1); Tue, 24 Aug 2021 02:41:19 +0800 Subject: Re: [PATCH 2/2] io_uring: add irq completion work to the head of task_list From: Hao Xu To: Jens Axboe Cc: io-uring@vger.kernel.org, Pavel Begunkov , Joseph Qi References: <20210823183648.163361-1-haoxu@linux.alibaba.com> <20210823183648.163361-3-haoxu@linux.alibaba.com> Message-ID: <0520539b-d366-1912-49a2-9e6126e4df1d@linux.alibaba.com> Date: Tue, 24 Aug 2021 02:41:18 +0800 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:78.0) Gecko/20100101 Thunderbird/78.12.0 MIME-Version: 1.0 In-Reply-To: <20210823183648.163361-3-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 2021/8/24 上午2:36, Hao Xu 写道: > Now we have a lot of task_work users, some are just to complete a req > and generate a cqe. Let's put the work at the head position of the > task_list, so that it can be handled quickly and thus to reduce > avg req latency. an explanatory case: > > origin timeline: > submit_sqe-->irq-->add completion task_work > -->run heavy work0~n-->run completion task_work > now timeline: > submit_sqe-->irq-->add completion task_work > -->run completion task_work-->run heavy work0~n > > Signed-off-by: Hao Xu sorry, sent this old version by mistake, will send latest version later. the latest one is to add high priority task_work to the front of task_list in the time order, not the reverse order.