From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S266572AbUBLUQs (ORCPT ); Thu, 12 Feb 2004 15:16:48 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S266574AbUBLUQs (ORCPT ); Thu, 12 Feb 2004 15:16:48 -0500 Received: from sccrmhc12.comcast.net ([204.127.202.56]:57485 "EHLO sccrmhc12.comcast.net") by vger.kernel.org with ESMTP id S266572AbUBLUQq (ORCPT ); Thu, 12 Feb 2004 15:16:46 -0500 Message-ID: <402BDF40.5040601@namesys.com> Date: Thu, 12 Feb 2004 12:17:04 -0800 From: Hans Reiser User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.6) Gecko/20040113 X-Accept-Language: en-us, en MIME-Version: 1.0 To: Jon Burgess CC: Rik van Riel , linux kernel , reiserfs-dev Subject: Re: ext2/3 performance regression in 2.6 vs 2.4 for small interleaved writes References: <402B580E.3000404@jburgess.uklinux.net> In-Reply-To: <402B580E.3000404@jburgess.uklinux.net> X-Enigmail-Version: 0.83.3.0 X-Enigmail-Supports: pgp-inline, pgp-mime Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Jon Burgess wrote: > Rik van Riel wrote: > >> Just for fun, could you also try measuring how long it takes >> to read back the files in question ? >> >> Both individually and in parallel... >> > The original code did the read back as well, I stripped it out to make > the code smaller to post. > It was the read back performance that I was most interested in. I > found that ext2/3 interleave all the blocks on the disk. With 2 stream > the read performance is 50%, 4 streams give 25% etc. > > I have one really bad case where I record a TV stream at 500kByte/s + > a radio one at 25kByte/s. These blocks are interleaved on the disk and > the read performance of the radio stream is reduced by the data ratio, > i.e. 1:20, so I get a miserable read performance of ~ 1MB/s. > > I found that ext2, ext3 and Reiserfs behave similarly. Try Reiser4, it will probably cure it for you nicely. I will be surprised if it does not, please let me know your results. I would expect that tweaking the block preallocation code to preallocate more should cure it for ReiserFS V3 also.... > XFS and JFS appear to coalesce the data blocks during the write phase > and can read the data back at near maximum performance. > > Jon > > - > 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/ > >