Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261862AbTILTJ1 (ORCPT ); Fri, 12 Sep 2003 15:09:27 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261863AbTILTJ1 (ORCPT ); Fri, 12 Sep 2003 15:09:27 -0400 Received: from e1.ny.us.ibm.com ([32.97.182.101]:7926 "EHLO e1.ny.us.ibm.com") by vger.kernel.org with ESMTP id S261862AbTILTJY (ORCPT ); Fri, 12 Sep 2003 15:09:24 -0400 Date: Fri, 12 Sep 2003 11:58:07 -0700 From: "Martin J. Bligh" To: Jesse Barnes , Tim Hockin cc: Andi Kleen , linux-kernel@vger.kernel.org Subject: Re: Memory mapped IO vs Port IO Message-ID: <223220000.1063393087@flay> In-Reply-To: <20030912182430.GA1043@sgi.com> References: <20030911192550.7dfaf08c.ak@suse.de.suse.lists.linux.kernel> <1063308053.4430.37.camel@huykhoi.suse.lists.linux.kernel> <20030912162713.GA4852@sgi.com.suse.lists.linux.kernel> <20030912174807.GA629@sgi.com.suse.lists.linux.kernel> <20030912111148.A15308@hockin.org> <20030912182430.GA1043@sgi.com> X-Mailer: Mulberry/2.1.2 (Linux/x86) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 650 Lines: 17 >> Also - a perhaps more useful test is a write followed by a read. > > Well, someone else will have to run that test. On Altix, a read() is > freakishly expensive, and I'm not really interested in showing everyone > how bad it is ;) I find percentile comparisons useful for hiding the embarassement of occasional hardware realities ;-) (ie what's the speed *ratio* between the two types of read). M. - 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/