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=-2.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,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 4E611C433FF for ; Tue, 30 Jul 2019 01:34:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 22D91206A2 for ; Tue, 30 Jul 2019 01:34:48 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="CFUP9PSQ" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730561AbfG3Ber (ORCPT ); Mon, 29 Jul 2019 21:34:47 -0400 Received: from mail-ot1-f67.google.com ([209.85.210.67]:41759 "EHLO mail-ot1-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729221AbfG3Ber (ORCPT ); Mon, 29 Jul 2019 21:34:47 -0400 Received: by mail-ot1-f67.google.com with SMTP id o101so64591446ota.8 for ; Mon, 29 Jul 2019 18:34:46 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=yqbOvv5+RVFDatXbu+9VaKNcbmnxhKKhVA039vocC6g=; b=CFUP9PSQyUTa4dYoXGJ6YIq+0NIVATEtlv/sGUy6fqezMQgpdUGGeHW2G60llLO3Mx SozoyiGtiAdJAGS8vZdiFWzSq+9WYX2KXbXIVqNzIJoCJnPXgBjlvI0MR3LPNBBythJo MjGo/Z8YBqldgAxkAmWzcceb2EiMe6LKOGk5m7qoRaoynaLEeKWUYCA8QFUdsb8ijzGj 5c1cRV1VwAdfCarRLlZesopzWgbCsH9XvR1apaz6jCZx2ByqFNniOqKSfMewPZMzO2kw dJEWxUXrBIWHBLq96/NPT7+tzCyRbb/epHF8YKfgqwopZe1vhrH/YGxvfIGoyD3ME6E3 5AvA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=yqbOvv5+RVFDatXbu+9VaKNcbmnxhKKhVA039vocC6g=; b=jXeZ5mUF8x82Fyu6tgtNy53hokxUpabQy+6aCxPeYbalwel4X2AzX0sF4chDZ6DACF Di2i6FcXGCwRcbo3R+/9N2dFmm66c1uBq6iyWLUXXqz2HQWQ9wE8qpb/nUzEmjr3kf7U JQGTrfa9OeKi6V/Ki6lWQ9cciVPn0OuwsoO3RQcij0hnhZK5p+r4sGNAePy252NiXMwO k7El5bm47sU7gISd/8l3O+2yywR93du4+f9WXCRxSLvhywL6MDZy9WXKKSTaRWUflc8H qE9Bo69cALAnEN/ZPfsFbv7KFtSq/7LDd8cnSRQrXsCk3lGnqeijW1Y/eLaK2vyjE/85 8mVg== X-Gm-Message-State: APjAAAUBPatuVrxEzfqmP+DXI6kAx7OqtC50i9DeeHDFQfPmoLCdDgLv 2QLphBXTRgQYavZVf0CZtKI= X-Google-Smtp-Source: APXvYqzitU6A+d+m1YtF6eesDDCxcyl/8J8EkDRmYWuTsSYYg6eNCRAjh7bsF8Vyu0tN83KOESldSg== X-Received: by 2002:a9d:5e11:: with SMTP id d17mr66497894oti.50.1564450486595; Mon, 29 Jul 2019 18:34:46 -0700 (PDT) Received: from JosephdeMacBook-Pro.local ([205.204.117.23]) by smtp.gmail.com with ESMTPSA id m21sm20222138otl.70.2019.07.29.18.34.42 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 29 Jul 2019 18:34:45 -0700 (PDT) Subject: Re: [RFC] performance regression with "ext4: Allow parallel DIO reads" To: Dave Chinner , Jan Kara Cc: Joseph Qi , Andreas Dilger , Theodore Ts'o , Ext4 Developers List , Xiaoguang Wang , Liu Bo References: <29d50d24-f8e7-5ef4-d4d8-3ea6fb1c6ed3@gmail.com> <6DADA28C-542F-45F6-ADB0-870A81ABED23@dilger.ca> <15112e38-94fe-39d6-a8e2-064ff47187d5@linux.alibaba.com> <20190728225122.GG7777@dread.disaster.area> From: Joseph Qi Message-ID: <960bb915-20cc-26a0-7abc-bfca01aa39c0@gmail.com> Date: Tue, 30 Jul 2019 09:34:39 +0800 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.11; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: <20190728225122.GG7777@dread.disaster.area> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-ext4-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org On 19/7/29 06:51, Dave Chinner wrote: > On Fri, Jul 26, 2019 at 09:12:07AM +0800, Joseph Qi wrote: >> >> >> On 19/7/26 05:20, Andreas Dilger wrote: >>> >>>> On Jul 23, 2019, at 5:17 AM, Joseph Qi wrote: >>>> >>>> Hi Ted & Jan, >>>> Could you please give your valuable comments? >>> >>> It seems like the original patches should be reverted? There is no data >> >> From my test result, yes. >> I've also tested libaio with iodepth 16, it behaves the same. Here is the test >> data for libaio 4k randrw: >> >> ------------------------------------------------------------------------------------------- >> w/ parallel dio reads | READ 78313KB/s, 19578, 1698.70us | WRITE 78313KB/s, 19578, 4837.60us >> ------------------------------------------------------------------------------------------- >> w/o parallel dio reads| READ 387774KB/s, 96943, 1009.73us | WRITE 387656KB/s，96914, 308.87us >> ------------------------------------------------------------------------------------------- >> >> Since this commit went into upstream long time ago，to be precise, Linux >> 4.9, I wonder if someone else has also observed this regression, or >> anything I missed? > > I suspect that the second part of this set of mods that Jan had > planned to do (on the write side to use shared locking as well) > did not happen and so the DIO writes are serialising the workload. > Thanks for the inputs, Dave. Hi Jan, Could you please confirm this? If so, should we revert this commit at present? Thanks, Joseph