From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S263005AbTIRHnp (ORCPT ); Thu, 18 Sep 2003 03:43:45 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S263006AbTIRHnp (ORCPT ); Thu, 18 Sep 2003 03:43:45 -0400 Received: from gprs145-63.eurotel.cz ([160.218.145.63]:28288 "EHLO amd.ucw.cz") by vger.kernel.org with ESMTP id S263005AbTIRHno (ORCPT ); Thu, 18 Sep 2003 03:43:44 -0400 Date: Thu, 18 Sep 2003 09:43:31 +0200 From: Pavel Machek To: richard.brunner@amd.com Cc: alan@lxorguk.ukuu.org.uk, davidsen@tmr.com, zwane@linuxpower.ca, linux-kernel@vger.kernel.org Subject: Re: [PATCH] 2.6 workaround for Athlon/Opteron prefetch errata Message-ID: <20030918074331.GA386@elf.ucw.cz> References: <99F2150714F93F448942F9A9F112634C0638B1DE@txexmtae.amd.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <99F2150714F93F448942F9A9F112634C0638B1DE@txexmtae.amd.com> X-Warning: Reading this can be dangerous to your mental health. User-Agent: Mutt/1.5.3i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Hi! > I think Alan brought up a very good point. Even if you > use a generic kernel that avoids prefetch use on Athlon > (which I am opposed to), it doesn't solve the problem > of user space programs detecting that the ISA supports > prefetch and using prefetch instructions and hitting the > errata on Athlon. > > The user space problem worries me more, because the expectation > is that if CPUID says the program can use perfetch, it could > and should regardless of what the kernel decided to do here. User programs should not rely on cpuid; they should read /proc/cpuinfo exactly because this kind of errata. Pavel -- When do you have a heart between your knees? [Johanka's followup: and *two* hearts?]