Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Mon, 12 Nov 2001 16:53:53 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Mon, 12 Nov 2001 16:53:44 -0500 Received: from tourian.nerim.net ([62.4.16.79]:34055 "HELO tourian.nerim.net") by vger.kernel.org with SMTP id ; Mon, 12 Nov 2001 16:53:25 -0500 Message-ID: <3BF044D3.8060503@free.fr> Date: Mon, 12 Nov 2001 22:53:23 +0100 From: Lionel Bouton User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:0.9.5+) Gecko/20011110 X-Accept-Language: en-us MIME-Version: 1.0 To: Steve Lord Cc: "'linux-kernel@vger.kernel.org'" Subject: Re: File System Performance In-Reply-To: <3BF02702.34C21E75@zip.com.au>, <00b201c16b81$9d7aaba0$5101a8c0@pbc.adelphia.net> <3BEFF9D1.3CC01AB3@zip.com.au> <00da01c16ba2$96aeda00$5101a8c0@pbc.adelphia.net> <3BF02702.34C21E75@zip.com.au> <1005595583.13307.5.camel@jen.americas.sgi.com> <3BF03402.87D44589@zip.com.au> <1005600431.13303.10.camel@jen.americas.sgi.com> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org > > > >I tried an experiment which puzzled me somwhat: > >> mount /xfs >> cd /xfs/lord/xfs-linux >> time tar cf /dev/null linux >> > >real 0m7.743s >user 0m0.510s >sys 0m1.380s > >>hdparm -t /dev/sda5 >> > >/dev/sda5: > Timing buffered disk reads: 64 MB in 3.76 seconds = 17.02 MB/sec > >>du -sk linux >> >173028 linux > >The tar got ~21 Mbytes/sec. > Things I'll check : 0/ rerun this test !!! 1/ is there cache on the scsi controler ? 2/ xfs data cached at mount ? (I don't believe so) 3/ "hdparm -t" is on crack. 4/ du reports a disk usage way ahead of files' sizes total (don't know xfs enough to estimate this propability) and tar won't read the whole "du -sk" data. 2/ "time mount /xfs" could help (if mount + tar times are below expected, this case can be eliminated). 3/ ask hdparm's maintener. 4/ tar, check tar size. - 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/