From mboxrd@z Thu Jan 1 00:00:00 1970 From: Al Boldi 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 Message-ID: <200701122235.30288.a1426z@gawab.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset="windows-1256" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Content-Disposition: inline Sender: linux-raid-owner@vger.kernel.org To: Justin Piszcz Cc: linux-kernel@vger.kernel.org, linux-raid@vger.kernel.org, xfs@oss.sgi.com List-Id: linux-raid.ids 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