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=-3.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, UNPARSEABLE_RELAY,URIBL_BLOCKED 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 35B24C433E7 for ; Wed, 14 Oct 2020 03:32:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D7D0320B1F for ; Wed, 14 Oct 2020 03:32:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729449AbgJNDcM (ORCPT ); Tue, 13 Oct 2020 23:32:12 -0400 Received: from out20-110.mail.aliyun.com ([115.124.20.110]:47844 "EHLO out20-110.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729395AbgJNDcL (ORCPT ); Tue, 13 Oct 2020 23:32:11 -0400 X-Alimail-AntiSpam: AC=CONTINUE;BC=0.1063232|-1;CH=green;DM=|CONTINUE|false|;DS=CONTINUE|ham_enroll_verification|0.0163685-0.00131857-0.982313;FP=0|0|0|0|0|-1|-1|-1;HT=ay29a033018047207;MF=wangyugui@e16-tech.com;NM=1;PH=DS;RN=2;RT=2;SR=0;TI=SMTPD_---.IiwWrR6_1602646328; Received: from 192.168.2.112(mailfrom:wangyugui@e16-tech.com fp:SMTPD_---.IiwWrR6_1602646328) by smtp.aliyun-inc.com(10.147.41.120); Wed, 14 Oct 2020 11:32:09 +0800 Date: Wed, 14 Oct 2020 11:32:11 +0800 From: Wang Yugui To: Dave Chinner Subject: Re: dbench throughput on xfs over hardware limit(6Gb/s) Cc: linux-xfs@vger.kernel.org In-Reply-To: <20201013230521.GB7391@dread.disaster.area> References: <20201013221113.F0A0.409509F4@e16-tech.com> <20201013230521.GB7391@dread.disaster.area> Message-Id: <20201014113211.2372.409509F4@e16-tech.com> MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-Mailer: Becky! ver. 2.75.01 [en] Precedence: bulk List-ID: X-Mailing-List: linux-xfs@vger.kernel.org > On Tue, Oct 13, 2020 at 10:11:13PM +0800, Wang Yugui wrote: > > Hi, > > > > dbench throughput on xfs over hardware limit(6Gb/s=750MB/s). > > > > Is this a bug or some feature of performance optimization? > > dbench measures page cache throughput, not physical IO throughput. > This sort of results is expected. We use 'dbench -s', so it should be physical IO. -s Use synchronous file IO on all file operations. we check 'dbench -s' with 'strace -ff -o s.log', we can see 'O_SYNC' in openat(). Best Regards Wang Yugui (wangyugui@e16-tech.com) 2020/10/14