Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S264661AbTFLBBI (ORCPT ); Wed, 11 Jun 2003 21:01:08 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S264662AbTFLBBI (ORCPT ); Wed, 11 Jun 2003 21:01:08 -0400 Received: from dyn-ctb-210-9-241-68.webone.com.au ([210.9.241.68]:16900 "EHLO chimp.local.net") by vger.kernel.org with ESMTP id S264661AbTFLBBB (ORCPT ); Wed, 11 Jun 2003 21:01:01 -0400 Message-ID: <3EE7D3DB.10607@cyberone.com.au> Date: Thu, 12 Jun 2003 11:14:03 +1000 From: Nick Piggin User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.3) Gecko/20030327 Debian/1.3-4 X-Accept-Language: en MIME-Version: 1.0 To: Steven Pratt CC: linux-kernel , Andrew Morton Subject: Re: 2.5.70-mm2 causes performance drop of random read O_DIRECT References: <3EE5190D.3070401@austin.ibm.com> <3EE522AA.7020200@cyberone.com.au> <3EE5E5AA.6020901@austin.ibm.com> <3EE67F38.9030702@cyberone.com.au> <3EE747BD.6010408@austin.ibm.com> In-Reply-To: <3EE747BD.6010408@austin.ibm.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1633 Lines: 53 Steven Pratt wrote: > Nick Piggin wrote: > >> Steven Pratt wrote: >> >>> Nick Piggin wrote: >>> >>>> Steven Pratt wrote: >>>> >>>>> Starting in 2.5.70-mm2 and continuing in the mm tree, there is a >>>>> significant degrade in random read for block devices using >>>>> O_DIRECT. The drop occurs for all block sizes and ranges from >>>>> 30%-40. CPU usage is also lower although it may already be so low >>>>> as to be irrelavent. >>>> >>>> >>>> Hi Steven, this is quite likely to be an io scheduler problem. >>>> Is your test program rawread v2.1.5? >>> >>> >>> This test was actually using 2.1.4, but the only difference in the >>> 2.1.5 version is a fix for the test label array for the aio versions >>> of the test. No functional change, just fixed the outputed test >>> description. >>> >>>> What is the command line you are using to invoke the program? >>> >>> >>> rawread -t6 -p8 -m1 -d2 -s4096 -n65536 -l1 -z -x >>> >>> Which you can find if you follow either results link and look in the >>> benchmark directory where all raw benchmark out put is stored. >> >> >> OK thanks, I can now reproduce this! I'll work on it. > > > Looks like Andrew beat you to it. Both 2.5.70-mm7 and mm8 are back up > to the previous performance levels for random reads. > No, that was me ;) Odd, I was still seeing a regression with mm7, but thats fixed in mm8. Thanks for testing. - 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/