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=-2.2 required=3.0 tests=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 D8379C2BA2B for ; Fri, 10 Apr 2020 10:14:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AD62C2166E for ; Fri, 10 Apr 2020 10:14:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726177AbgDJKOq (ORCPT ); Fri, 10 Apr 2020 06:14:46 -0400 Received: from mx2.suse.de ([195.135.220.15]:45500 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725893AbgDJKOp (ORCPT ); Fri, 10 Apr 2020 06:14:45 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id 55CB3AB5F; Fri, 10 Apr 2020 10:14:44 +0000 (UTC) Received: by ds.suse.cz (Postfix, from userid 10065) id 5FC56DA72D; Fri, 10 Apr 2020 12:14:06 +0200 (CEST) Date: Fri, 10 Apr 2020 12:14:06 +0200 From: David Sterba To: Qu Wenruo Cc: Xing Zhengjun , kernel test robot , David Sterba , Linus Torvalds , Leonard Lausen , LKML , lkp@01.org Subject: Re: [LKP] [btrfs] 8d47a0d8f7: fio.write_bw_MBps -28.6% regression Message-ID: <20200410101406.GI5920@suse.cz> Reply-To: dsterba@suse.cz Mail-Followup-To: dsterba@suse.cz, Qu Wenruo , Xing Zhengjun , kernel test robot , David Sterba , Linus Torvalds , Leonard Lausen , LKML , lkp@01.org References: <20190513031733.GI31424@shao2-debian> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: Mutt/1.5.23.1-rc1 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Apr 10, 2020 at 02:44:55PM +0800, Qu Wenruo wrote: > On 2020/4/10 下午2:34, Xing Zhengjun wrote: > > Hi Wenruo, > > > >    We test it in v5.6, the issue still exist, do you have time to take a > > look at this? Thanks. > > This is expected. > > The extra check brings new overhead mostly equal to another CRC32 run. > > We believe it's worthy, as our read time tree checker has exposed quite > some bit flip corruption. The test probably runs on a PMEM device so there's no slowdown from the actual IO and the in-memory checks are measurable, though 28% is a lot, I'd expect something like 5-10% at most. From mboxrd@z Thu Jan 1 00:00:00 1970 Content-Type: multipart/mixed; boundary="===============6430923179971934225==" MIME-Version: 1.0 From: David Sterba To: lkp@lists.01.org Subject: Re: [btrfs] 8d47a0d8f7: fio.write_bw_MBps -28.6% regression Date: Fri, 10 Apr 2020 12:14:06 +0200 Message-ID: <20200410101406.GI5920@suse.cz> In-Reply-To: List-Id: --===============6430923179971934225== Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable On Fri, Apr 10, 2020 at 02:44:55PM +0800, Qu Wenruo wrote: > On 2020/4/10 =E4=B8=8B=E5=8D=882:34, Xing Zhengjun wrote: > > Hi Wenruo, > > = > > =C2=A0=C2=A0 We test it in v5.6, the issue still exist, do you have tim= e to take a > > look at this? Thanks. > = > This is expected. > = > The extra check brings new overhead mostly equal to another CRC32 run. > = > We believe it's worthy, as our read time tree checker has exposed quite > some bit flip corruption. The test probably runs on a PMEM device so there's no slowdown from the actual IO and the in-memory checks are measurable, though 28% is a lot, I'd expect something like 5-10% at most. --===============6430923179971934225==--