From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030723AbWKORVf (ORCPT ); Wed, 15 Nov 2006 12:21:35 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1030728AbWKORVf (ORCPT ); Wed, 15 Nov 2006 12:21:35 -0500 Received: from mx2.mail.elte.hu ([157.181.151.9]:3040 "EHLO mx2.mail.elte.hu") by vger.kernel.org with ESMTP id S1030723AbWKORVe (ORCPT ); Wed, 15 Nov 2006 12:21:34 -0500 Date: Wed, 15 Nov 2006 18:20:03 +0100 From: Ingo Molnar To: Andi Kleen Cc: Eric Dumazet , akpm@osdl.org, Arjan van de Ven , Jeremy Fitzhardinge , linux-kernel@vger.kernel.org Subject: Re: [PATCH] i386-pda UP optimization Message-ID: <20061115172003.GA20403@elte.hu> References: <1158046540.2992.5.camel@laptopd505.fenrus.org> <1158047806.2992.7.camel@laptopd505.fenrus.org> <200611151227.04777.dada1@cosmosbay.com> <200611151232.31937.ak@suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200611151232.31937.ak@suse.de> User-Agent: Mutt/1.4.2.2i X-ELTE-SpamScore: -4.4 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-4.4 required=5.9 tests=ALL_TRUSTED,AWL,BAYES_00 autolearn=no SpamAssassin version=3.0.3 -3.3 ALL_TRUSTED Did not pass through any untrusted hosts -2.6 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0004] 1.5 AWL AWL: From: address is in the auto white-list X-ELTE-VirusStatus: clean Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org * Andi Kleen wrote: > On Wednesday 15 November 2006 12:27, Eric Dumazet wrote: > > Seeing %gs prefixes used now by i386 port, I recalled seeing strange > > oprofile results on Opteron machines. > > > > I really think %gs prefixes can be expensive in some (most ?) cases, > > even if the Intel/AMD docs say they are free. > > They aren't free, just very cheap. Eric's test shows a 5% slowdown. That's far from cheap. Ingo