From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261355AbTIONtS (ORCPT ); Mon, 15 Sep 2003 09:49:18 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261361AbTIONtS (ORCPT ); Mon, 15 Sep 2003 09:49:18 -0400 Received: from lightning.hereintown.net ([141.157.132.3]:29326 "EHLO lightning.hereintown.net") by vger.kernel.org with ESMTP id S261355AbTIONsS (ORCPT ); Mon, 15 Sep 2003 09:48:18 -0400 Subject: Re: [PATCH] 2.6 workaround for Athlon/Opteron prefetch errata From: Chris Meadors To: linux-kernel@vger.kernel.org In-Reply-To: <3F65B2BD.9000206@cyberone.com.au> References: <200309151146.h8FBkXcw001170@81-2-122-30.bradfords.org.uk> <3F65B2BD.9000206@cyberone.com.au> Content-Type: text/plain Message-Id: <1063633563.215.16.camel@clubneon.priv.hereintown.net> Mime-Version: 1.0 X-Mailer: Ximian Evolution 1.4.3 Date: 15 Sep 2003 09:46:04 -0400 Content-Transfer-Encoding: 7bit X-Scanner: exiscan for exim4 (http://duncanthrax.net/exiscan/) *19ytiD-0003Re-Ty*onm0/2n.i6Q* Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 2003-09-15 at 08:38, Nick Piggin wrote: > OK, the reason why I don't like the sound of this is because the size > of your option set has now been squared, and its no longer "make these > CPUs work". The way I see the config option working is, having a sub-menu that says something like, "Select the CPU the kernel will be run on." From there you can pick one CPU. This sets the in kernel optimizations for that CPU, along with the work arounds (obviously). It also sets the compiler flags for the padding, and "-march=[CPU]". Then in a sub-menu of this menu, there is an "Advanced processor selection". The help text would be something like, "In addition to the primary processor selected above, also allow this kernel to be booted on the processors selected below. Selecting this option disables some of the optimizations for the primary processor." Just turning on that option would change the "-march=" to "-mcpu=". Then in the menu one could select from any of the CPUs listed. Each one would enable the work around code to allow the built kernel to run correctly on a machine with a different CPU. I see this as sort of like the advanced partition selection, or the compiled in fonts. > I can see an argument for cache line size but thats about it. I can't > think of my optimisations that should be done on one architecture but > not another. Don't forget the compiler optimization flags. A kernel built with "-march" may not run on any other CPUs. -- Chris