Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030190AbXALTr0 (ORCPT ); Fri, 12 Jan 2007 14:47:26 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1030183AbXALTr0 (ORCPT ); Fri, 12 Jan 2007 14:47:26 -0500 Received: from [212.12.190.102] ([212.12.190.102]:33210 "EHLO raad.intranet" rhost-flags-FAIL-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1030182AbXALTrZ (ORCPT ); Fri, 12 Jan 2007 14:47:25 -0500 X-Greylist: delayed 818 seconds by postgrey-1.27 at vger.kernel.org; Fri, 12 Jan 2007 14:47:23 EST From: Al Boldi To: Justin Piszcz Subject: Re: Linux Software RAID 5 Performance Optimizations: 2.6.19.1: (211MB/s read & 195MB/s write) Date: Fri, 12 Jan 2007 22:49:13 +0300 User-Agent: KMail/1.5 Cc: linux-kernel@vger.kernel.org, linux-raid@vger.kernel.org, xfs@oss.sgi.com References: In-Reply-To: MIME-Version: 1.0 Content-Disposition: inline Message-Id: <200701122235.30288.a1426z@gawab.com> Content-Type: text/plain; charset="windows-1256" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1054 Lines: 31 Justin Piszcz wrote: > RAID 5 TWEAKED: 1:06.41 elapsed @ 60% CPU > > This should be 1:14 not 1:06(was with a similarly sized file but not the > same) the 1:14 is the same file as used with the other benchmarks. and to > get that I used 256mb read-ahead and 16384 stripe size ++ 128 > max_sectors_kb (same size as my sw raid5 chunk size) max_sectors_kb is probably your key. On my system I get twice the read performance by just reducing max_sectors_kb from default 512 to 192. Can you do a fresh reboot to shell and then: $ cat /sys/block/hda/queue/* $ cat /proc/meminfo $ echo 3 > /proc/sys/vm/drop_caches $ dd if=/dev/hda of=/dev/null bs=1M count=10240 $ echo 192 > /sys/block/hda/queue/max_sectors_kb $ echo 3 > /proc/sys/vm/drop_caches $ dd if=/dev/hda of=/dev/null bs=1M count=10240 Thanks! -- Al - 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/