From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756482AbZCABic (ORCPT ); Sat, 28 Feb 2009 20:38:32 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755001AbZCABiY (ORCPT ); Sat, 28 Feb 2009 20:38:24 -0500 Received: from casper.infradead.org ([85.118.1.10]:57550 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753666AbZCABiX (ORCPT ); Sat, 28 Feb 2009 20:38:23 -0500 Date: Sat, 28 Feb 2009 17:38:13 -0800 From: Arjan van de Ven To: Andi Kleen Cc: "H. Peter Anvin" , Andi Kleen , David Miller , torvalds@linux-foundation.org, mingo@elte.hu, nickpiggin@yahoo.com.au, sqazi@google.com, linux-kernel@vger.kernel.org, tglx@linutronix.de Subject: Re: [patch] x86, mm: pass in 'total' to __copy_from_user_*nocache() Message-ID: <20090228173813.6d86c0ef@infradead.org> In-Reply-To: <20090301014822.GG26292@one.firstfloor.org> References: <20090228092450.3ded2db5@infradead.org> <20090228.160651.228301019.davem@davemloft.net> <20090301004003.GF26292@one.firstfloor.org> <49A9D6CA.30906@zytor.com> <20090228163811.48b1de72@infradead.org> <20090301014822.GG26292@one.firstfloor.org> Organization: Intel X-Mailer: Claws Mail 3.7.0 (GTK+ 2.14.7; i386-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.infradead.org See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, 1 Mar 2009 02:48:22 +0100 Andi Kleen wrote: > > the entire point of using movntq and friends was to save half the > > I thought the point was to not pollute caches? At least that is > what I remember being told when I merged the patch. > the reason that movntq and co are faster is because you avoid the write-allocate behavior of the caches.... the cache polluting part of it I find hard to buy for general use (as this discussion shows)... that will be extremely hard to measure as a real huge thing, while the WA part is like a 1.5x to 2x thing. -- Arjan van de Ven Intel Open Source Technology Centre For development, discussion and tips for power savings, visit http://www.lesswatts.org