From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1764780AbXGPAlT (ORCPT ); Sun, 15 Jul 2007 20:41:19 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1760811AbXGPAlH (ORCPT ); Sun, 15 Jul 2007 20:41:07 -0400 Received: from tomts25.bellnexxia.net ([209.226.175.188]:57736 "EHLO tomts25-srv.bellnexxia.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760123AbXGPAlG (ORCPT ); Sun, 15 Jul 2007 20:41:06 -0400 Date: Sun, 15 Jul 2007 20:41:02 -0400 From: Mathieu Desnoyers To: Andi Kleen Cc: Alexey Dobriyan , akpm@linux-foundation.org, linux-kernel@vger.kernel.org, Adrian Bunk Subject: Re: [patch 4/8] Immediate Value - Add kconfig menus Message-ID: <20070716004102.GD26411@Krystal> References: <20070714012439.285079881@polymtl.ca> <20070714012623.839969254@polymtl.ca> <20070714072801.GB5822@martell.zuzino.mipt.ru> <20070714152734.GB4737@Krystal> <20070716003322.GA26835@one.firstfloor.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline In-Reply-To: <20070716003322.GA26835@one.firstfloor.org> X-Editor: vi X-Info: http://krystal.dyndns.org:8080 X-Operating-System: Linux/2.6.21.3-grsec (i686) X-Uptime: 20:38:49 up 8 days, 14:44, 3 users, load average: 0.11, 0.12, 0.20 User-Agent: Mutt/1.5.13 (2006-08-11) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org * Andi Kleen (andi@firstfloor.org) wrote: > > On embedded systems, the tradeoff is not the same. The immediate values > > trade a little bit of system memory (to keep the pointers to the > > variable and instruction as well as the size of the variable, only used > > when the variable is updated) in order to remove cache line hot paths. > > Please remove the Kconfig. I don't think it makes sense. Such optimizations > should be always enabled. We don't have CONFIG_GO_FASTER configs normally. > Don't introduce them now. > > > > > Also, embedded systems with physically read-only memory clearly does not > > want to enable this. > > We always patch the x86 kernel, so they have to deal with it anyways. > The x86 port doesn't support XIP. > > -Andi Hehe, good timing, please see the immediate-values-kconfig-embedded.patch I just sent. ;) Well, the idea is to give the option to every architecture in the embedded menu, which is not limited to X86. -- Mathieu Desnoyers Computer Engineering Ph.D. Student, Ecole Polytechnique de Montreal OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68