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 7B428C48BE5 for ; Mon, 21 Jun 2021 20:05:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5B1056120D for ; Mon, 21 Jun 2021 20:05:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230028AbhFUUHm (ORCPT ); Mon, 21 Jun 2021 16:07:42 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50386 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231668AbhFUUHl (ORCPT ); Mon, 21 Jun 2021 16:07:41 -0400 Received: from mail-il1-x12c.google.com (mail-il1-x12c.google.com [IPv6:2607:f8b0:4864:20::12c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 58889C061574 for ; Mon, 21 Jun 2021 13:05:26 -0700 (PDT) Received: by mail-il1-x12c.google.com with SMTP id b5so4464100ilc.12 for ; Mon, 21 Jun 2021 13:05:26 -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=WAHZ8Vz2CwykfGGX5mNg7moax8bM1FVKxI9y5zaUxRo=; b=fSYB3k2zxiTixDG0FzieNm8sxSEpgbEwcSqrWdWmeo4e2ZYkP3R12nr4DUd+rYyGLY mr7xDQX5qqemxxLys3J1GD5+k5nLoz9pxQiBT/9IW6BlQ/FGhlbmEzCmK4lAUFr6Haew DWwNr0CgbiBqKVmhqCWxxQe6COqP7+ChDh45GLVmZZeRo0RunBqR9HusT7JgMLj6prJy C55RXku4p35elny+VDSZUelcmNB/roqzqA3LWKP73TnhT2NzQEIL/Vv/0GYslqF8zB6x 9NzMifprzG7RIfsbwDrNUrpusE1GnyfQ8Cm5gWJ+yKPOC2LEU06ufqYChfkupTbM7/CE hyOw== 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=WAHZ8Vz2CwykfGGX5mNg7moax8bM1FVKxI9y5zaUxRo=; b=P3mo9uF6NPS2/fqKnvLvoIZGsPQbh1JjE0qLv/Jt+BB+qEeAoPlhZc0foYyQwGzVNm DD1xd7DwBOzg05Qet39QGkPkf8Ge7z1FllC2yYnkcXSIbpyco1P9BQZG4W7fOfV9PtmP q3BhA+gaJfNNxo4XtqLfJRcNpdDb5KUFlJSs5lXxLRthfVI2h/x20P9cYiHHFRDaeN55 GaKoSCdWGm/Dk393Wob+B5vl3k4XSSgbg9gXgGmsxvMnQcasM6dMo/wrmYQ0oI801/CF q2QQQe88S5lvyRTtzx940IkqDJyIwAeH81/nQsAykw3Yfj82YwUWnCdFEOtHc8U8676o +2Hw== X-Gm-Message-State: AOAM530RqMwCtUZc23c69tjyXeOH2wBMx4zMO60IYirZbB1SyONE/iJa EDQU4ycOzbKcz2938yJONdtQcQ== X-Google-Smtp-Source: ABdhPJwMq0IDYFERSTpcx/JHQfuyCQUwIVcQDzUz0AwidBKGfmBDEQHkaeEheqvAmPNFAF7SiQ5wAA== X-Received: by 2002:a92:cda2:: with SMTP id g2mr1181691ild.3.1624305925736; Mon, 21 Jun 2021 13:05:25 -0700 (PDT) Received: from [192.168.1.134] ([198.8.77.61]) by smtp.gmail.com with ESMTPSA id m13sm6854247ila.80.2021.06.21.13.05.24 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 21 Jun 2021 13:05:25 -0700 (PDT) Subject: Re: [PATCH v3] io_uring: reduce latency by reissueing the operation To: Olivier Langlois , Pavel Begunkov , io-uring@vger.kernel.org, linux-kernel@vger.kernel.org References: <4deda7761d61c189f4e2581828f852c8a1acb723.1624303174.git.olivier@trillion01.com> From: Jens Axboe Message-ID: <82b94c49-b18d-94b2-cb8d-43cf54e402f3@kernel.dk> Date: Mon, 21 Jun 2021 14:05:24 -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: <4deda7761d61c189f4e2581828f852c8a1acb723.1624303174.git.olivier@trillion01.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 6/21/21 1:22 PM, Olivier Langlois wrote: > It is quite frequent that when an operation fails and returns EAGAIN, > the data becomes available between that failure and the call to > vfs_poll() done by io_arm_poll_handler(). > > Detecting the situation and reissuing the operation is much faster > than going ahead and push the operation to the io-wq. This now looks pretty good to me. I know you had some data associated with this, would be great to include it in the commit message. -- Jens Axboe