From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030317AbVH0FeH (ORCPT ); Sat, 27 Aug 2005 01:34:07 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1030314AbVH0FeG (ORCPT ); Sat, 27 Aug 2005 01:34:06 -0400 Received: from linares.terra.com.br ([200.176.10.195]:57813 "EHLO linares.terra.com.br") by vger.kernel.org with ESMTP id S1030315AbVH0FeF (ORCPT ); Sat, 27 Aug 2005 01:34:05 -0400 X-Terra-Karma: -2% X-Terra-Hash: 9fa27bbb24781ce970d756773e087895 Date: Sat, 27 Aug 2005 02:34:00 -0300 To: Mitchell Blank Jr Cc: Andi Kleen , "David S. Miller" , rml@novell.com, akpm@osdl.org, linux-kernel@vger.kernel.org Subject: Re: [patch] IBM HDAPS accelerometer driver, with probing. Message-ID: <20050827053359.GB15782@mandriva.com> Mail-Followup-To: acme@ghostprotocols.net, Mitchell Blank Jr , Andi Kleen , "David S. Miller" , rml@novell.com, akpm@osdl.org, linux-kernel@vger.kernel.org References: <1125094725.18155.120.camel@betsy> <20050826225848.GC28191@mipter.zuzino.mipt.ru> <20050826.161537.03992270.davem@davemloft.net> <20050827040622.GH91880@gaz.sfgoth.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20050827040622.GH91880@gaz.sfgoth.com> X-Url: http://advogato.org/person/acme User-Agent: Mutt/1.5.9i From: acme@ghostprotocols.net (Arnaldo Carvalho de Melo) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Em Fri, Aug 26, 2005 at 09:06:22PM -0700, Mitchell Blank Jr escreveu: > Andi Kleen wrote: > > - it doesn't seem to help that much on modern CPUs with good > > branch prediction and big icaches anyways. > > Really? I would think that as pipelines get deeper (although that trend > seems to have stopped, thankfully) and Icache-miss penalties get relatively > larger we'd see unlikely() becoming MORE of a benefit, not less. Storing > the used part of a "hot" function in 1 Icacheline instead of 4 seems like > an obvious win. > > Personally I've never found unlikely() to be ugly; if anything I think > it serves as a nice little human-readable comment about whats going on > in the control-flow. I guess I'm in the minority on that one, though. Hey, even if unlikely was: #define unlikely(x) (x) I'd find it useful :-) - Arnaldo