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=-10.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING, SPF_HELO_NONE,SPF_PASS,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 9CF08C433E0 for ; Thu, 14 Jan 2021 22:53:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 694C92389B for ; Thu, 14 Jan 2021 22:53:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731012AbhANWxF (ORCPT ); Thu, 14 Jan 2021 17:53:05 -0500 Received: from mx2.suse.de ([195.135.220.15]:53636 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730840AbhANWxE (ORCPT ); Thu, 14 Jan 2021 17:53:04 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 5D507AA6F; Thu, 14 Jan 2021 22:52:22 +0000 (UTC) Received: by ds.suse.cz (Postfix, from userid 10065) id A3910DA7EE; Thu, 14 Jan 2021 23:50:28 +0100 (CET) Date: Thu, 14 Jan 2021 23:50:28 +0100 From: David Sterba To: Xing Zhengjun Cc: dsterba@suse.cz, kernel test robot , Josef Bacik , David Sterba , =?iso-8859-1?Q?Ren=E9?= Rebe , LKML , lkp@lists.01.org, lkp@intel.com, ying.huang@intel.com, feng.tang@intel.com, linux-btrfs@vger.kernel.org Subject: Re: [LKP] Re: [btrfs] e076ab2a2c: fio.write_iops -18.3% regression Message-ID: <20210114225028.GF6430@twin.jikos.cz> Reply-To: dsterba@suse.cz Mail-Followup-To: dsterba@suse.cz, Xing Zhengjun , kernel test robot , Josef Bacik , David Sterba , =?iso-8859-1?Q?Ren=E9?= Rebe , LKML , lkp@lists.01.org, lkp@intel.com, ying.huang@intel.com, feng.tang@intel.com, linux-btrfs@vger.kernel.org References: <20210112153614.GA2015@xsang-OptiPlex-9020> <20210112154529.GT6430@twin.jikos.cz> <979aee28-c603-a187-e03f-29957c7b94d6@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <979aee28-c603-a187-e03f-29957c7b94d6@linux.intel.com> User-Agent: Mutt/1.5.23.1-rc1 (2014-03-12) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jan 13, 2021 at 01:58:18PM +0800, Xing Zhengjun wrote: > > > On 1/12/2021 11:45 PM, David Sterba wrote: > > On Tue, Jan 12, 2021 at 11:36:14PM +0800, kernel test robot wrote: > >> Greeting, > >> > >> FYI, we noticed a -18.3% regression of fio.write_iops due to commit: > >> > >> > >> commit: e076ab2a2ca70a0270232067cd49f76cd92efe64 ("btrfs: shrink delalloc pages instead of full inodes") > >> https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git master > >> > >> > >> in testcase: fio-basic > >> on test machine: 192 threads Intel(R) Xeon(R) CPU @ 2.20GHz with 192G memory > >> with following parameters: > >> > >> disk: 1SSD > >> fs: btrfs > >> runtime: 300s > >> nr_task: 8 > >> rw: randwrite > >> bs: 4k > >> ioengine: sync > >> test_size: 256g > > Though I do a similar test (emulating bit torrent workload), it's a bit > > extreme as it's 4k synchronous on a huge file. It always takes a lot of > > time but could point out some concurrency issues namely on faster > > devices. There are 8 threads possibly competing for the same inode lock > > or other locks related to it. > > > > The mentioned commit fixed another perf regression on a much more common > > workload (untgrring files), so at this point drop in this fio workload > > is inevitable. > > Do you have a plan to fix it? Thanks. My plan is to find somebody who will fix it. Thanks.