From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758486Ab2AFCE2 (ORCPT ); Thu, 5 Jan 2012 21:04:28 -0500 Received: from terminus.zytor.com ([198.137.202.10]:50161 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757278Ab2AFCE1 (ORCPT ); Thu, 5 Jan 2012 21:04:27 -0500 Message-ID: <4F06566B.8080708@zytor.com> Date: Thu, 05 Jan 2012 18:03:23 -0800 From: "H. Peter Anvin" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:8.0) Gecko/20111115 Thunderbird/8.0 MIME-Version: 1.0 To: Andi Kleen CC: Jan Beulich , mingo@elte.hu, tglx@linutronix.de, linux-kernel@vger.kernel.org Subject: Re: x86-64: memset()/memcpy() not fully standards compliant References: <4F05BBFE020000780006A983@nat28.tlf.novell.com> <20120105182846.GQ11715@one.firstfloor.org> <4F0630CC.7050001@zytor.com> <20120106014748.GS11715@one.firstfloor.org> In-Reply-To: <20120106014748.GS11715@one.firstfloor.org> X-Enigmail-Version: 1.3.3 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 01/05/2012 05:47 PM, Andi Kleen wrote: >> >> Is that still true, and do we even use string instructions still on >> those old CPUs? Jan's fixes don't introduce any additional delays in >> the non-string-instruction paths. > > Yes various of the CPUs with bugs used string instructions. > Which CPUs are you talking about here? > > Both string and non string instructions are used on modern CPUs, > so making any of that slower is not a good idea. > Obviously not, but I'm perfectly fine turning REP_GOOD off on old broken CPUs. -hpa -- H. Peter Anvin, Intel Open Source Technology Center I work for Intel. I don't speak on their behalf.