Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1765150AbYBAMN6 (ORCPT ); Fri, 1 Feb 2008 07:13:58 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1763692AbYBAMNs (ORCPT ); Fri, 1 Feb 2008 07:13:48 -0500 Received: from mail-relay-02.mailcluster.net ([77.221.130.214]:44454 "EHLO mail-relay-02.mailcluster.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758781AbYBAMNr (ORCPT ); Fri, 1 Feb 2008 07:13:47 -0500 Message-ID: <47A3078C.10704@vlnb.net> Date: Fri, 01 Feb 2008 14:50:36 +0300 From: Vladislav Bolkhovitin User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.13) Gecko/20060501 Fedora/1.7.13-1.1.fc5 X-Accept-Language: en-us, ru, en MIME-Version: 1.0 To: David Dillow CC: Bart Van Assche , landman@scalableinformatics.com, James.Bottomley@hansenpartnership.com, linux-scsi@vger.kernel.org, rdreier@cisco.com, linux-kernel@vger.kernel.org, "Nicholas A. Bellinger" , fujita.tomonori@lab.ntt.co.jp, scst-devel@lists.sourceforge.net, akpm@linux-foundation.org, FUJITA Tomonori , torvalds@linux-foundation.org Subject: Re: [Scst-devel] Integration of SCST in the mainstream Linux kernel References: <20080130083239E.fujita.tomonori@lab.ntt.co.jp> <20080130195635T.tomof@acm.org> <1201785938.7280.105.camel@haakon2.linux-iscsi.org> <47A1EE54.6000005@vlnb.net> <47A1F67C.4020300@scalableinformatics.com> <1201803135.21160.8.camel@lap75545.ornl.gov> In-Reply-To: <1201803135.21160.8.camel@lap75545.ornl.gov> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1465 Lines: 37 David Dillow wrote: > On Thu, 2008-01-31 at 18:08 +0100, Bart Van Assche wrote: > >>If anyone has a suggestion for a better test than dd to compare the >>performance of SCSI storage protocols, please let it know. > > > xdd on /dev/sda, sdb, etc. using -dio to do direct IO seems to work > decently, though it is hard (ie, impossible) to get a repeatable > sequence of IO when using higher queue depths, as it uses threads to > generate multiple requests. This utility seems to be a good one, but it's basically the same as disktest, although much more advanced. > You may also look at sgpdd_survey from Lustre's iokit, but I've not done > much with that -- it uses the sg devices to send lowlevel SCSI commands. Yes, it might be worth to try. Since fundamentally it's the same as O_DIRECT dd, but with a bit less overhead on the initiator side (hence less initiator side latency), most likely it will show ever bigger difference, than it is with dd. > I've been playing around with some benchmark code using libaio, but it's > not in generally usable shape. > > xdd: > http://www.ioperformance.com/products.htm > > Lustre IO Kit: > http://manual.lustre.org/manual/LustreManual16_HTML/DynamicHTML-20-1.html -- 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/