Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759678Ab2JLPOR (ORCPT ); Fri, 12 Oct 2012 11:14:17 -0400 Received: from one.firstfloor.org ([213.235.205.2]:51416 "EHLO one.firstfloor.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758028Ab2JLPOQ (ORCPT ); Fri, 12 Oct 2012 11:14:16 -0400 Date: Fri, 12 Oct 2012 17:14:10 +0200 From: Andi Kleen To: "Ma, Ling" Cc: Andi Kleen , "mingo@elte.hu" , "hpa@zytor.com" , "tglx@linutronix.de" , "linux-kernel@vger.kernel.org" , "iant@google.com" Subject: Re: [PATCH RFC 2/2] [x86] Optimize copy_page by re-arranging instruction sequence and saving register Message-ID: <20121012151410.GB16230@one.firstfloor.org> References: <1349958548-1868-1-git-send-email-ling.ma@intel.com> <20121012133554.GA16230@one.firstfloor.org> 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 Content-Length: 842 Lines: 22 On Fri, Oct 12, 2012 at 02:54:54PM +0000, Ma, Ling wrote: > > If you can't test the CPUs who run this code I think it's safer if you > > add a new variant for Atom, not change the existing well tested code. > > Otherwise you risk performance regressions on these older CPUs. > > I found one older machine, and tested the code on it, the results between them are almost the same as below(attached cpu info). Was that a P4 (family 15)? Those were the main users. There were a few others, but they are obscure (early steppings of K8) -Andi -- ak@linux.intel.com -- Speaking for myself only. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/