From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964800AbVHYE7A (ORCPT ); Thu, 25 Aug 2005 00:59:00 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S964798AbVHYE7A (ORCPT ); Thu, 25 Aug 2005 00:59:00 -0400 Received: from ns.miraclelinux.com ([219.118.163.66]:53397 "EHLO mail01.miraclelinux.com") by vger.kernel.org with ESMTP id S964800AbVHYE67 (ORCPT ); Thu, 25 Aug 2005 00:58:59 -0400 Date: Thu, 25 Aug 2005 13:54:20 +0900 (JST) Message-Id: <20050825.135420.640917643.hyoshiok@miraclelinux.com> To: ak@suse.de Cc: linux-kernel@vger.kernel.org, hyoshiok@miraclelinux.com Subject: Re: [RFC] [PATCH] cache pollution aware __copy_from_user_ll() From: Hiro Yoshioka In-Reply-To: References: <20050823.081246.846946371.hyoshiok@miraclelinux.com.suse.lists.linux.kernel> <20050824.231156.278740508.hyoshiok@miraclelinux.com.suse.lists.linux.kernel> X-Mailer: Mew version 3.3 on XEmacs 21.4.13 (Rational FORTRAN) Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org From: Andi Kleen > > 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 Thanks for your comments. I'll consider it. Regards, Hiro