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=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,UNPARSEABLE_RELAY,USER_AGENT_SANE_1 autolearn=no 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 6AADCC433E0 for ; Tue, 23 Mar 2021 04:11:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2CECB619AF for ; Tue, 23 Mar 2021 04:11:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229464AbhCWEKa (ORCPT ); Tue, 23 Mar 2021 00:10:30 -0400 Received: from out30-57.freemail.mail.aliyun.com ([115.124.30.57]:38438 "EHLO out30-57.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229500AbhCWEKC (ORCPT ); Tue, 23 Mar 2021 00:10:02 -0400 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R131e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=alimailimapcm10staff010182156082;MF=joseph.qi@linux.alibaba.com;NM=1;PH=DS;RN=5;SR=0;TI=SMTPD_---0UT1nzlU_1616472598; Received: from B-D1K7ML85-0059.local(mailfrom:joseph.qi@linux.alibaba.com fp:SMTPD_---0UT1nzlU_1616472598) by smtp.aliyun-inc.com(127.0.0.1); Tue, 23 Mar 2021 12:09:59 +0800 Subject: Re: [ANNOUNCEMENT] io_uring SQPOLL sharing changes To: Jens Axboe , Xiaoguang Wang , Pavel Begunkov , io-uring , Hao Xu References: <30563957-709a-73a2-7d54-58419089d61a@linux.alibaba.com> <1afd5237-4363-9178-917e-3132ba1b89c3@kernel.dk> From: Joseph Qi Message-ID: <293e88d8-7fa5-edf4-226c-1e42dec9af67@linux.alibaba.com> Date: Tue, 23 Mar 2021 12:09:58 +0800 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:78.0) Gecko/20100101 Thunderbird/78.7.1 MIME-Version: 1.0 In-Reply-To: <1afd5237-4363-9178-917e-3132ba1b89c3@kernel.dk> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org On 3/22/21 10:49 PM, Jens Axboe wrote: > On 3/21/21 11:54 PM, Xiaoguang Wang wrote: >> hi Pavel, >> >>> Hey, >>> >>> You may have already noticed, but there will be a change how SQPOLL >>> is shared in 5.12. In particular, SQPOLL may be shared only by processes >>> belonging to the same thread group. If this condition is not fulfilled, >>> then it silently creates a new SQPOLL task. >> >> Thanks for your kindly reminder, currently we only share sqpoll thread >> in threads belonging to one same process. > > That's good to know, imho it is also the only thing that _really_ makes > sense to do. > > Since we're on the topic, are you actively using the percpu thread setup > that you sent out patches for earlier? That could still work within > the new scheme of having io threads, but I'd be curious to know first > if you guys are actually using it. > Yes, we've already used percpu sqthread feature in our production environment, in which 16 application threads share the same sqthread, and it gains ~20% rt improvement compared with libaio. Thanks, Joseph