From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758769Ab1FWC3Q (ORCPT ); Wed, 22 Jun 2011 22:29:16 -0400 Received: from one.firstfloor.org ([213.235.205.2]:46793 "EHLO one.firstfloor.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758371Ab1FWC3P (ORCPT ); Wed, 22 Jun 2011 22:29:15 -0400 Date: Thu, 23 Jun 2011 04:29:11 +0200 From: Andi Kleen To: "Ma, Ling" Cc: Andi Kleen , "mingo@elte.hu" , "hpa@zytor.com" , "tglx@linutronix.de" , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH RFC] [x86] Optimize copy-page by reducing impact from HW prefetch Message-ID: <20110623022911.GM3263@one.firstfloor.org> References: <1308351117-32452-1-git-send-email-ling.ma@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.4.2.2i Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jun 23, 2011 at 09:01:19AM +0800, Ma, Ling wrote: > Yes, I also have tested 64bit atom, it got 11.6% improvement. That's a nice improvement, however I should add that in my experience copy_page micro benchmark improvements do not necessarily translate to real world improvements. Most simple micro benchmark do not simulate the typical page fault access pattern very well. > Because older CPU almost all use prefetch-next-line mechanism, the patch should be useful to them. Old in this case is P4 and ancient early stepping K8 only. -Andi