From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S265306AbUBFCSA (ORCPT ); Thu, 5 Feb 2004 21:18:00 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S265329AbUBFCR7 (ORCPT ); Thu, 5 Feb 2004 21:17:59 -0500 Received: from mail-06.iinet.net.au ([203.59.3.38]:23985 "HELO mail.iinet.net.au") by vger.kernel.org with SMTP id S265306AbUBFCRx (ORCPT ); Thu, 5 Feb 2004 21:17:53 -0500 Message-ID: <4022F94C.30605@cyberone.com.au> Date: Fri, 06 Feb 2004 13:17:48 +1100 From: Nick Piggin User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.6) Gecko/20040122 Debian/1.6-1 X-Accept-Language: en MIME-Version: 1.0 To: Mattias Wadenstein CC: linux-kernel@vger.kernel.org Subject: Re: Performance issue with 2.6 md raid0 References: <402263E7.6010903@cyberone.com.au> In-Reply-To: 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 Mattias Wadenstein wrote: >On Fri, 6 Feb 2004, Nick Piggin wrote: > > >>Mattias Wadenstein wrote: >> >> >>>Greetings. >>> >>>While testing a file server to store a couple of TB in resonably large >>>files (>1G), I noticed an odd performance behaviour with the md raid0 in a >>>pristine 2.6.2 kernel as compared to a 2.4.24 kernel. >>> >>>When striping two md raid5:s, instead of going from about 160-200MB/s for >>>a single raid5 to 300M/s for the raid0 in 2.4.24, the 2.6.2 kernel gave >>>135M/s in single stream read performance. >>> >>Can you try booting with elevator=deadline please? >> > >Ok, then I get 253267 kB/s write and 153187 kB/s read from the raid0. A >bit better, but still nowhere near the 2.4.24 numbers. > >For a single raid5, 158028 kB/s write and 162944 kB/s read. > > Any idea what is holding back performance? Is it IO or CPU bound? Can you get a profile of each kernel while doing a read please?