From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753935Ab1HCJsk (ORCPT ); Wed, 3 Aug 2011 05:48:40 -0400 Received: from cn.fujitsu.com ([222.73.24.84]:63318 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1753565Ab1HCJsf convert rfc822-to-8bit (ORCPT ); Wed, 3 Aug 2011 05:48:35 -0400 Message-ID: <4E391986.90108@cn.fujitsu.com> Date: Wed, 03 Aug 2011 17:48:54 +0800 From: Gui Jianfeng User-Agent: Mozilla/5.0 (Windows NT 5.1; rv:5.0) Gecko/20110624 Thunderbird/5.0 MIME-Version: 1.0 To: Shaohua Li CC: Vivek Goyal , Jens Axboe , linux-kernel@vger.kernel.org Subject: Re: fio posixaio performance problem References: <4E38C314.8070305@cn.fujitsu.com> <4E3902C7.9050907@cn.fujitsu.com> In-Reply-To: X-MIMETrack: Itemize by SMTP Server on mailserver/fnst(Release 8.5.1FP4|July 25, 2010) at 2011-08-03 17:47:35, Serialize by Router on mailserver/fnst(Release 8.5.1FP4|July 25, 2010) at 2011-08-03 17:47:35 Content-Type: text/plain; charset=GB2312 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2011-8-3 16:22, Shaohua Li wrote: > 2011/8/3 Gui Jianfeng : >> On 2011-8-3 15:38, Shaohua Li wrote: >>> 2011/8/3 Gui Jianfeng : >>>> Hi, >>>> >>>> I ran a fio test to simulate qemu-kvm io behaviour. >>>> When job number is greater than 2, IO performance is >>>> really bad. >>>> >>>> 1 thread: aggrb=15,129KB/s >>>> 4 thread: aggrb=1,049KB/s >>>> >>>> Kernel: lastest upstream >>>> >>>> Any idea? >>>> >>>> --- >>>> [global] >>>> runtime=30 >>>> time_based=1 >>>> size=1G >>>> group_reporting=1 >>>> ioengine=posixaio >>>> exec_prerun='echo 3 > /proc/sys/vm/drop_caches' >>>> thread=1 >>>> >>>> [kvmio-1] >>>> description=kvmio-1 >>>> numjobs=4 >>>> rw=write >>>> bs=4k >>>> direct=1 >>>> filename=/mnt/sda4/1G.img >>> Hmm, the test runs always about 15M/s at my side regardless how many threads. >> >> CFQ£¿ > yes. > >> what's the slice_idle value? > default value. I didn't change it. Hmm, I use a sata disk, and can reproduce this bug every time... Thanks, Gui > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ > >