From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755907Ab0ESCF0 (ORCPT ); Tue, 18 May 2010 22:05:26 -0400 Received: from fgwmail7.fujitsu.co.jp ([192.51.44.37]:55316 "EHLO fgwmail7.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754604Ab0ESCFY (ORCPT ); Tue, 18 May 2010 22:05:24 -0400 X-SecurityPolicyCheck-FJ: OK by FujitsuOutboundMailChecker v1.3.1 From: KOSAKI Motohiro To: Jeff Moyer Subject: Re: [PATCH 0/4 v4] ext3/4: enhance fsync performance when using CFQ Cc: kosaki.motohiro@jp.fujitsu.com, linux-kernel@vger.kernel.org, linux-ext4@vger.kernel.org, jens.axboe@oracle.com, vgoyal@redhat.com In-Reply-To: <1274206820-17071-1-git-send-email-jmoyer@redhat.com> References: <1274206820-17071-1-git-send-email-jmoyer@redhat.com> Message-Id: <20100519105706.8821.A69D9226@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-Mailer: Becky! ver. 2.50.07 [ja] Date: Wed, 19 May 2010 11:05:20 +0900 (JST) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Jeff, > This patch series addresses a performance problem experienced when running > io_zone with small file sizes (from 4KB up to 8MB) and including fsync in > the timings. A good example of this would be the following command line: > iozone -s 64 -e -f /mnt/test/iozone.0 -i 0 > As the file sizes get larger, the performance improves. By the time the > file size is 16MB, there is no difference in performance between runs > using CFQ and runs using deadline. The storage in my testing was a NetApp > array connected via a single fibre channel link. When testing against a > single SATA disk, the performance difference is not apparent. offtopic: Can this patch help to reduce a pain of following much small files issue? http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=578635 Now, userland folks think sync() is faster than fsync() on ext4. I don't hope spread this unrecommended habit widely.