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=-7.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, 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 95549C1975A for ; Wed, 25 Mar 2020 05:50:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6B16820714 for ; Wed, 25 Mar 2020 05:50:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726104AbgCYFuM (ORCPT ); Wed, 25 Mar 2020 01:50:12 -0400 Received: from mga14.intel.com ([192.55.52.115]:65262 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725832AbgCYFuM (ORCPT ); Wed, 25 Mar 2020 01:50:12 -0400 IronPort-SDR: +mCIFifJJG7HD+DzpfuRxGyDiCbpI5zvN7Ddo+w77n0hs8bpodKNmXWbQkGc9Y4+mRGr8T3TA5 l/OyySCE8kVA== X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by fmsmga103.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 24 Mar 2020 22:50:11 -0700 IronPort-SDR: 0VosqJrdoBsE2H7KRynW52/btwD78KKSC5cMCm427w2v8i/D//7WMDd+LIDjsQtF6R6Fo4v8AO uBYEbk3wky7w== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.72,303,1580803200"; d="scan'208";a="357716875" Received: from xingzhen-mobl1.ccr.corp.intel.com (HELO [10.238.5.64]) ([10.238.5.64]) by fmsmga001.fm.intel.com with ESMTP; 24 Mar 2020 22:50:09 -0700 Subject: Re: [LKP] Re: [ext4] b1b4705d54: filebench.sum_bytes_mb/s -20.2% regression From: Xing Zhengjun To: Rong Chen , Jan Kara , "Theodore Y. Ts'o" , Matthew Bobrowski Cc: Ritesh Harjani , LKML , Linus Torvalds , lkp@lists.01.org References: <20191224005915.GW2760@shao2-debian> <20200107134106.GD25547@quack2.suse.cz> <20200107165708.GA3619@mit.edu> <20200107172824.GK25547@quack2.suse.cz> <7ec6b078-7b09-fb87-8ad2-a328e96c5bf9@linux.intel.com> Message-ID: <49a59199-53af-206f-d07c-5c8c45f498b3@linux.intel.com> Date: Wed, 25 Mar 2020 13:50:09 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.6.0 MIME-Version: 1.0 In-Reply-To: <7ec6b078-7b09-fb87-8ad2-a328e96c5bf9@linux.intel.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org ping... The issue still exists in v5.6-rc7. On 3/4/2020 4:15 PM, Xing Zhengjun wrote: > Hi Matthew, > >  We test it in v5.6-rc4, the issue still exist, do you have time to > take a look at this? Thanks. > > On 1/8/2020 10:31 AM, Rong Chen wrote: >> >> >> On 1/8/20 1:28 AM, Jan Kara wrote: >>> On Tue 07-01-20 11:57:08, Theodore Y. Ts'o wrote: >>>> On Tue, Jan 07, 2020 at 02:41:06PM +0100, Jan Kara wrote: >>>>> Hello, >>>>> >>>>> On Tue 24-12-19 08:59:15, kernel test robot wrote: >>>>>> FYI, we noticed a -20.2% regression of filebench.sum_bytes_mb/s >>>>>> due to commit: >>>>>> >>>>>> >>>>>> commit: b1b4705d54abedfd69dcdf42779c521aa1e0fbd3 ("ext4: introduce >>>>>> direct I/O read using iomap infrastructure") >>>>>> https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git >>>>>> master >>>>>> >>>>>> in testcase: filebench >>>>>> on test machine: 8 threads Intel(R) Core(TM) i7-4770 CPU @ 3.40GHz >>>>>> with 8G memory >>>>>> with following parameters: >>>>>> >>>>>>     disk: 1HDD >>>>>>     fs: ext4 >>>>>>     test: fivestreamreaddirect.f >>>>>>     cpufreq_governor: performance >>>>>>     ucode: 0x27 >>>>> I was trying to reproduce this but I failed with my test VM. I had >>>>> SATA SSD >>>>> as a backing store though so maybe that's what makes a difference. >>>>> Maybe >>>>> the new code results in somewhat more seeks because the five >>>>> threads which >>>>> compete in submitting sequential IO end up being more interleaved? >>>> A "-20.2% regression" should be read as a "20.2% performance >>>> improvement" is zero-day kernel speak. >>> Are you sure? I can see: >>> >>>       58.30 ±  2%     -20.2%      46.53        filebench.sum_bytes_mb/s >>> >>> which implies to me previously the throughput was 58 MB/s and after the >>> commit it was 46 MB/s? >>> >>> Anyway, in my testing that commit made no difference in that benchmark >>> whasoever (getting around 97 MB/s for each thread before and after the >>> commit). >>>                                 Honza >> >> We're sorry for the misunderstanding, "-20.2%" means the change of >> filebench.sum_bytes_mb/s, >> "regression" means the explanation of this change from LKP. >> >> Best Regards, >> Rong Chen >> _______________________________________________ >> LKP mailing list -- lkp@lists.01.org >> To unsubscribe send an email to lkp-leave@lists.01.org > -- Zhengjun Xing