From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751107AbVHXQSn (ORCPT ); Wed, 24 Aug 2005 12:18:43 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751112AbVHXQSn (ORCPT ); Wed, 24 Aug 2005 12:18:43 -0400 Received: from cantor.suse.de ([195.135.220.2]:64996 "EHLO mx1.suse.de") by vger.kernel.org with ESMTP id S1751107AbVHXQSm (ORCPT ); Wed, 24 Aug 2005 12:18:42 -0400 To: Hiro Yoshioka Cc: linux-kernel@vger.kernel.org Subject: Re: [RFC] [PATCH] cache pollution aware __copy_from_user_ll() References: <20050818.201138.607962419.hyoshiok@miraclelinux.com.suse.lists.linux.kernel> <98df96d30508181629d85edb5@mail.gmail.com.suse.lists.linux.kernel> <20050823.081246.846946371.hyoshiok@miraclelinux.com.suse.lists.linux.kernel> <20050824.231156.278740508.hyoshiok@miraclelinux.com.suse.lists.linux.kernel> From: Andi Kleen Date: 24 Aug 2005 18:18:36 +0200 In-Reply-To: <20050824.231156.278740508.hyoshiok@miraclelinux.com.suse.lists.linux.kernel> Message-ID: User-Agent: Gnus/5.09 (Gnus v5.9.0) Emacs/21.3 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Hiro Yoshioka writes: > Hi, > > The following patch does not use MMX regsiters so that we don't have > to worry about save/restore the FPU/MMX states. > > What do you think? Performance will probably be bad on K7 Athlons - those have a microcoded movnti which is quite slow. Also BTW I don't see any code anywhere that tests the CPUID bits, so your code will fail spectacularly on a PII that didn't do SSE (intel user copy used to be enabled on those) One way to solve this might be to use different code using alternative() -Andi