From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S263465AbTD1MHK (ORCPT ); Mon, 28 Apr 2003 08:07:10 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S263538AbTD1MHK (ORCPT ); Mon, 28 Apr 2003 08:07:10 -0400 Received: from hermes.fachschaften.tu-muenchen.de ([129.187.202.12]:51949 "HELO hermes.fachschaften.tu-muenchen.de") by vger.kernel.org with SMTP id S263465AbTD1MHJ (ORCPT ); Mon, 28 Apr 2003 08:07:09 -0400 Date: Mon, 28 Apr 2003 14:19:20 +0200 From: Adrian Bunk To: Andi Kleen Cc: torvalds@transmeta.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH] Support worst case cache line sizes as config option Message-ID: <20030428121920.GE27064@fs.tum.de> References: <20030427022346.GA27933@averell> <20030428091616.GA27064@fs.tum.de> <20030428114717.GA6904@averell> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20030428114717.GA6904@averell> User-Agent: Mutt/1.4.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Apr 28, 2003 at 01:47:17PM +0200, Andi Kleen wrote: > On Mon, Apr 28, 2003 at 11:16:16AM +0200, Adrian Bunk wrote: > > Your X86_GENERIC is semantically equivalent to M386. > > M386 is tuning for the Intel 386 > > X86_GENERIC is "try to tune for all CPUs if possible" M386 says that the minimum CPU supported is the 386 - and all CPUs above are supported, too. E.g.: config X86_PPRO_FENCE bool depends on M686 || M586MMX || M586TSC || M586 || M486 || M386 default y config X86_F00F_BUG bool depends on M586MMX || M586TSC || M586 || M486 || M386 default y > > This doesn't work. E.g. MPENTIUMIII has the semantics of "support > > Pentium-III and above". If you want to compile a kernel that runs on > > both a Pentium-III and a Pentium-4 you choose MPENTIUMIII which implies > > X86_L1_CACHE_SHIFT=5 ... > > Admittedly the other options could be changed to > > default "4" if (MELAN || M486 || M386) && !X86_GENERIC > > but that looked a bit too ugly and it seems to work even without. Your approach as well as the approach I'm currently working on breaks the current semantics that a plain M386 produces a kernel that runs on all CPUs. > -Andi 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