Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262312AbTFJAAW (ORCPT ); Mon, 9 Jun 2003 20:00:22 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262316AbTFJAAV (ORCPT ); Mon, 9 Jun 2003 20:00:21 -0400 Received: from dyn-ctb-203-221-72-225.webone.com.au ([203.221.72.225]:40464 "EHLO chimp.local.net") by vger.kernel.org with ESMTP id S262312AbTFJAAS (ORCPT ); Mon, 9 Jun 2003 20:00:18 -0400 Message-ID: <3EE522AA.7020200@cyberone.com.au> Date: Tue, 10 Jun 2003 10:13:30 +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 Subject: Re: 2.5.70-mm2 causes performance drop of random read O_DIRECT References: <3EE5190D.3070401@austin.ibm.com> In-Reply-To: <3EE5190D.3070401@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: 720 Lines: 20 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? What is the command line you are using to invoke the program? - 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/