Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750836AbVI1UDK (ORCPT ); Wed, 28 Sep 2005 16:03:10 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750831AbVI1UDK (ORCPT ); Wed, 28 Sep 2005 16:03:10 -0400 Received: from mail.tmr.com ([64.65.253.246]:63383 "EHLO gaimboi.tmr.com") by vger.kernel.org with ESMTP id S1750827AbVI1UDI (ORCPT ); Wed, 28 Sep 2005 16:03:08 -0400 Message-ID: <433AF75F.2060208@tmr.com> Date: Wed, 28 Sep 2005 16:04:47 -0400 From: Bill Davidsen Organization: TMR Associates Inc, Schenectady NY User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.11) Gecko/20050729 X-Accept-Language: en-us, en MIME-Version: 1.0 To: Guy CC: "'Holger Kiehl'" , "'Mark Hahn'" , "'linux-raid'" , "'linux-kernel'" Subject: Re: Where is the performance bottleneck? References: <200508302305.j7UN5bE23350@www.watkins-home.com> In-Reply-To: <200508302305.j7UN5bE23350@www.watkins-home.com> 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 Content-Length: 1032 Lines: 25 Guy wrote: >In most of your results, your CPU usage is very high. Once you get to about >90% usage, you really can't do much else, unless you can improve the CPU >usage. > That seems one of the problems with software RAID, the calculations are done in the CPU and not dedicated hardware. As you move to the top end drive hardware the CPU gets to be a limit. I don't remember off the top of my head how threaded this code is, and if more CPUs will help. I see you are using RAID-1 for your system stuff, did one of the tests use RAID-0 over all the drives? Mirroring or XOR redundancy help stability but hurt performance. Was the 270MB/s with RAID-0 or ??? -- bill davidsen CTO TMR Associates, Inc Doing interesting things with small computers since 1979 - 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/