From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261478AbTIKRdk (ORCPT ); Thu, 11 Sep 2003 13:33:40 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261475AbTIKRbk (ORCPT ); Thu, 11 Sep 2003 13:31:40 -0400 Received: from amdext2.amd.com ([163.181.251.1]:12512 "EHLO amdext2.amd.com") by vger.kernel.org with ESMTP id S261440AbTIKRSm (ORCPT ); Thu, 11 Sep 2003 13:18:42 -0400 Message-ID: <99F2150714F93F448942F9A9F112634C0638B19A@txexmtae.amd.com> From: richard.brunner@amd.com To: ak@suse.de, davej@redhat.com cc: torvalds@osdl.org, linux-kernel@vger.kernel.org, akpm@osdl.org Subject: RE: [PATCH] 2.6 workaround for Athlon/Opteron prefetch errata Date: Thu, 11 Sep 2003 12:17:57 -0500 MIME-Version: 1.0 X-Mailer: Internet Mail Service (5.5.2653.19) X-WSS-ID: 137E71C02325899-01-01 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org > -----Original Message----- > From: Andi Kleen [mailto:ak@suse.de] > Sent: Thursday, September 11, 2003 7:29 AM > > On Thu, 11 Sep 2003 15:14:51 +0100 > Dave Jones wrote: > > > On Thu, Sep 11, 2003 at 04:01:08PM +0200, Andi Kleen wrote: > > > > > > What's wrong with the current status quo that just says > > > > "Athlon prefetch is broken"? > > > It doesn't fix user space for once. > > > > And for another, it cripples the earlier athlons which > > don't have this > > errata. Andi's fix at least makes prefetch work again on > > those boxes. > > It's also arguable that prefetch() helps the older K7's > > more than the > > affected ones. > > All Athlons have this Errata. I can trigger it on an old > 900Mhz pre XP Athlon too. You just have to use 3dnow prefetch > instead of SSE prefetch. > > BTW the older Athlons currently don't use prefetch because > the alternative > patcher does not handle 3dnow style prefetch. > Avoiding prefetch for all Athlons and earlier Opterons/Athlon64 even in the kernel can really tank performance. And as Andi says it still doesn't solve user mode from hitting the errata. ] -Rich ... ] AMD Fellow