From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261580AbTIOUzh (ORCPT ); Mon, 15 Sep 2003 16:55:37 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261582AbTIOUzh (ORCPT ); Mon, 15 Sep 2003 16:55:37 -0400 Received: from hermes.fachschaften.tu-muenchen.de ([129.187.202.12]:17862 "HELO hermes.fachschaften.tu-muenchen.de") by vger.kernel.org with SMTP id S261580AbTIOUzb (ORCPT ); Mon, 15 Sep 2003 16:55:31 -0400 Date: Mon, 15 Sep 2003 22:55:23 +0200 From: Adrian Bunk To: John Bradford Cc: davidsen@tmr.com, zwane@linuxpower.ca, linux-kernel@vger.kernel.org Subject: Re: [PATCH] 2.6 workaround for Athlon/Opteron prefetch errata Message-ID: <20030915205522.GP126@fs.tum.de> References: <200309150632.h8F6WnHb000589@81-2-122-30.bradfords.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200309150632.h8F6WnHb000589@81-2-122-30.bradfords.org.uk> User-Agent: Mutt/1.4.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Sep 15, 2003 at 07:32:49AM +0100, John Bradford wrote: >... > It should be possible, and straightforward, to compile a kernel which: > > 1. Supports, (I.E. has workarounds for), any combination of CPUs. > E.G. a kernel which supports 386s, and Athlons _only_ would not > need the F00F bug workaround. Currently '386' kernels include it, > because '386' means 'support 386 and above processors'. > > 2. Has compiler optimisations for one particular CPU. > E.G. the 386 and Athlon supporting kernel above could have > alignment optimised for either 386 or Athlon. >... That's the point where even I consider such a system to be too complex. If you want maximum performance compile a kernel specific for your system. Compiling a kernel that supports more than one CPU is for people that can even live with let's say a 10% performance penalty. If you want to run a kernel on both a 386 and an Athlon it's most likely non-optimal for both of them. > John. cu Adrian -- "Is there not promise of rain?" Ling Tan asked suddenly out of the darkness. There had been need of rain for many days. "Only a promise," Lao Er said. Pearl S. Buck - Dragon Seed