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,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS,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 91A8FC433E0 for ; Mon, 22 Mar 2021 14:50:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4F211619A2 for ; Mon, 22 Mar 2021 14:50:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230119AbhCVOtw (ORCPT ); Mon, 22 Mar 2021 10:49:52 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53772 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230129AbhCVOtX (ORCPT ); Mon, 22 Mar 2021 10:49:23 -0400 Received: from mail-io1-xd2b.google.com (mail-io1-xd2b.google.com [IPv6:2607:f8b0:4864:20::d2b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AE229C061574 for ; Mon, 22 Mar 2021 07:49:22 -0700 (PDT) Received: by mail-io1-xd2b.google.com with SMTP id k25so2088146iob.6 for ; Mon, 22 Mar 2021 07:49:22 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20150623.gappssmtp.com; s=20150623; h=subject:to:references:from:message-id:date:user-agent:mime-version :in-reply-to:content-language:content-transfer-encoding; bh=zbmqmyP4vA69N/YXo4MMAZFgfhUCEg914AmEuMVnxP4=; b=ZnypxfODvzxR31UKGqi06d1fFdGF15NlAaZAObOg2So+kEhARUeuljNu4VcPpQYK3N 45bzdq67oaIlIWKIE82Qt/NQOhwrYJT72Mspp19ridM8/CyvKtc6CqDczpAj0ZU0wiQ1 cHt4IKxbnugj5a2YVSQKCRvKVPDSD1oMYa8H2lvpzVHO53oCkwD5r3dP5j5E3q8sR9Ws PT/9kRKKhLQ15AWNxkSeAIFiqwv1HoqKDIdhKSVg6xhMj8OgqxpLmO1ZrE4brh/YnM1F Vc6UFmbqlcvM7YxRVzzjuyraCLKHBVG3OWU9RPC/hom/oyVa20SWUlHXeJZY3GQHCCFp wqvA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=zbmqmyP4vA69N/YXo4MMAZFgfhUCEg914AmEuMVnxP4=; b=aAtJus6EmV5zBgK7ZHeI2Bc4dfT1h8xwtuHE/TtfSSUR/TeGnPFwXN/LsaMcH5vk8J MXP5c/L2eoNHWtVdNRFYXnPxLi7DZkvDpHrrHEV9CkBfnUcDoqciVxuWPd2rYAzcQYUn t1l4w1Thn7bkXaW0T4AacW9FnMD2OMqLWX7Oa5kcS+GB2BZgb5mpyO/L4fCpvEdvglfE +d8HISwpQmYRq0wGnfaYoUZTu92nhb22KBMJmJdLOkvYkhr18FRZo5RQCnFnJ1UMcbja Ff4dKn7ttAdwXQujccDabYudRqwoY4WBJjV0IvkwJDyDdRU+1IAscaVauezW1JYjVRf/ TCNQ== X-Gm-Message-State: AOAM532Cuc8QEUbU4LzrgqPhtEvWmxO8ZKL9Q9gCd/v7h7fCnr37aJud hq43aBASXgNgLRx4PETHoyWuO+OeObfe2w== X-Google-Smtp-Source: ABdhPJwrqmoIazQd1kNxOBHagoHgpZk1uPjZ4TWiP8NljLKfK8UIyGfj+CU9imjzs3MiO6VcvbOblg== X-Received: by 2002:a02:7119:: with SMTP id n25mr11688793jac.48.1616424562309; Mon, 22 Mar 2021 07:49:22 -0700 (PDT) Received: from [192.168.1.30] ([65.144.74.34]) by smtp.gmail.com with ESMTPSA id k12sm7704852ios.2.2021.03.22.07.49.21 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 22 Mar 2021 07:49:21 -0700 (PDT) Subject: Re: [ANNOUNCEMENT] io_uring SQPOLL sharing changes To: Xiaoguang Wang , Pavel Begunkov , io-uring , joseph qi , Hao Xu References: <30563957-709a-73a2-7d54-58419089d61a@linux.alibaba.com> From: Jens Axboe Message-ID: <1afd5237-4363-9178-917e-3132ba1b89c3@kernel.dk> Date: Mon, 22 Mar 2021 08:49:21 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <30563957-709a-73a2-7d54-58419089d61a@linux.alibaba.com> 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 3/21/21 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. -- Jens Axboe