From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755108AbYIHTzt (ORCPT ); Mon, 8 Sep 2008 15:55:49 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753021AbYIHTzk (ORCPT ); Mon, 8 Sep 2008 15:55:40 -0400 Received: from casper.infradead.org ([85.118.1.10]:48476 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752618AbYIHTzk (ORCPT ); Mon, 8 Sep 2008 15:55:40 -0400 Date: Mon, 8 Sep 2008 12:55:25 -0700 From: Arjan van de Ven To: Linus Torvalds Cc: Ingo Molnar , "H. Peter Anvin" , x86 maintainers , Andrew Morton , Linux Kernel Mailing List Subject: Re: [git pull] x86 fixes Message-ID: <20080908125525.72bc1ad2@infradead.org> In-Reply-To: References: <200809081752.m88Hq6tn005080@askone.hos.anvin.org> <48C56D60.7010405@zytor.com> <20080908114619.741b6786@infradead.org> <48C57439.3040903@zytor.com> <20080908190249.GA21998@elte.hu> Organization: Intel X-Mailer: Claws Mail 3.5.0 (GTK+ 2.12.11; i386-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.infradead.org See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 8 Sep 2008 12:30:02 -0700 (PDT) Linus Torvalds wrote: > > I think there are realistically three classes: > > - _really_ old, to the point of being totally useless for SMP. > > This is really just 386 and clones. We _need_ a working WP for a > race-free access_ok(), and we need cmpxchg (and lately xadd). > > Smaller pains even on UP: bswap doesn't exist. invlpg doesn't > exist. I'd lump all cpus that don't have cpuid in this bucket too (eg half the 486es) simply because not having cpuid is painful in pretty much the same way. > - old. pre-cmov. i486 and pentium, and some clones. makes sense > - "modern 32-bit": PPro and better. Can take CMOV, MMX and TSC for > granted. again makes sense; question is if it makes sense to take PSE and PAE for granted as well (although PSE we can do runtime I suppose) > Hmm? Doesn't that sound like a sane model? it does to me; the only question is if we hit a new bucket with the various fancy string instructions that are in upcoming models; doing string/copy operations inlined for those guys will make a fourth bucket. -- If you want to reach me at my work email, use arjan@linux.intel.com For development, discussion and tips for power savings, visit http://www.lesswatts.org