From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261154AbVFWNM0 (ORCPT ); Thu, 23 Jun 2005 09:12:26 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262246AbVFWNMZ (ORCPT ); Thu, 23 Jun 2005 09:12:25 -0400 Received: from cantor2.suse.de ([195.135.220.15]:41355 "EHLO mx2.suse.de") by vger.kernel.org with ESMTP id S261154AbVFWNKK (ORCPT ); Thu, 23 Jun 2005 09:10:10 -0400 Date: Thu, 23 Jun 2005 15:10:05 +0200 From: Andi Kleen To: Eric Dumazet Cc: Andi Kleen , linux-kernel@vger.kernel.org, jh@suse.cz Subject: Re: [PATCH] x86_64 prefetchw() function can take into account CONFIG_MK8 / CONFIG_MPSC Message-ID: <20050623131004.GL14251@wotan.suse.de> References: <20050622.132241.21929037.davem@davemloft.net> <200506222242.j5MMgbxS009935@guinness.s2io.com> <20050622231300.GC14251@wotan.suse.de> <42BA81B2.4070108@cosmosbay.com> <20050623113150.GK14251@wotan.suse.de> <42BAB0BA.1010100@cosmosbay.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <42BAB0BA.1010100@cosmosbay.com> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jun 23, 2005 at 02:53:14PM +0200, Eric Dumazet wrote: > Andi Kleen a ?crit : > >On Thu, Jun 23, 2005 at 11:32:34AM +0200, Eric Dumazet wrote: > > > >>If we build a x86_64 kernel for an AMD64 or for an Intel EMT64, no need > >>to use alternative_input. > >>Reserve alternative_input only for a generic kernel. > > > > > >An EM64T kernel should still boot on AMD64 and vice versa. Rejected. > > > >-Andi > > > > > > OK, I wrongly assumed the 'MK8' or 'MPSC' choices were like x86 choices : > > A kernel compiled for a Pentium-4 will not run on a i486. > > But then what is the meaning of the choice "Generic-x86-64" in the > "Processor family" menu ? > The Help message is : CONFIG_GENERIC_CPU: Generic x86-64 CPU. Optimize for both. It's a catch all setting for future changes and does not do too much right now. It also won't pass any -mcpu=... arguments to gcc. This currently doesn't make any difference (gcc x86-64 default is to optimize for K8), but I assume it might at some point when gcc gets a "combined" mode that optimizes for both Intel and AMD CPUs. -Andi