From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S263376AbTLJCvI (ORCPT ); Tue, 9 Dec 2003 21:51:08 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S263400AbTLJCvI (ORCPT ); Tue, 9 Dec 2003 21:51:08 -0500 Received: from smtp12.eresmas.com ([62.81.235.112]:48022 "EHLO smtp12.eresmas.com") by vger.kernel.org with ESMTP id S263376AbTLJCvE (ORCPT ); Tue, 9 Dec 2003 21:51:04 -0500 Message-ID: <3FD68A14.90500@wanadoo.es> Date: Wed, 10 Dec 2003 03:51:00 +0100 From: Xose Vazquez Perez User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.0.1) Gecko/20021003 X-Accept-Language: gl, es, en MIME-Version: 1.0 To: linux-kernel@vger.kernel.org Subject: Re: bad performance on 2.4.23 References: X-Enigmail-Version: 0.63.3.0 X-Enigmail-Supports: pgp-inline, pgp-mime Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Spam-Score: 0.0 (/) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Marcelo Tosatti wrote: > About the high numbers on -ac and -aa: > > -ac includes rmap and the drop_behind() logic (I just posted the patch > against 2.4.23 to lkml). I believe its the reason for the read slowdowns > reported on lkml. > > -aa includes this patch which will increase the max readahead > significantly. Mind trying it? Sorry. I don't have any free machine to do this kind of tests. :( >>In 'Sequential Reads' and 'Sequential Writes', 'Maximum Latency' is _too much high_ >> >>2.4.23-pre4 8192 4096 256 5.10 6.83% 430.551 1602091.53 0.35501 0.31585 75 >>2.4.23-rc1 8192 4096 256 5.04 6.94% 432.486 1937701.66 0.33408 0.29884 73 > Now this is really odd. When did it started happening? It looks like between .20 and .23, included. Test was done by Randy Hron over a OSDL server: 4x700 mhz Pentium III Xeons with 1MB cache 3.75 GB RAM DAC960 Fiber channel to SCSI disks in RAID5 configuration more details at http://home.earthlink.net/~rwhron/kernel/bigbox.html what is very strange is that in two different tests and kernels (2.4.23-pre4 and2.4.23-rc1) 'Maximum Latency' is very high with 256 threads.