From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762466AbWLKF0w (ORCPT ); Mon, 11 Dec 2006 00:26:52 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1762413AbWLKF0w (ORCPT ); Mon, 11 Dec 2006 00:26:52 -0500 Received: from moutng.kundenserver.de ([212.227.126.186]:62345 "EHLO moutng.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1762431AbWLKF0v (ORCPT ); Mon, 11 Dec 2006 00:26:51 -0500 Message-ID: <457CEC0F.2030206@anagramm.de> Date: Mon, 11 Dec 2006 06:26:39 +0100 From: Clemens Koller User-Agent: Thunderbird 1.5.0.8 (Windows/20061025) MIME-Version: 1.0 To: Adrian Bunk CC: Folkert van Heusden , linux-kernel@vger.kernel.org Subject: Re: optimalisation for strlcpy (lib/string.c) References: <20061210212350.GC30197@vanheusden.com> <20061210231305.GG10351@stusta.de> In-Reply-To: <20061210231305.GG10351@stusta.de> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Provags-ID: kundenserver.de abuse@kundenserver.de login:224ad0fd4f2efe95e6ec4f0a3ca8a73c Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Hi, Adrian & Friends! >> Like the other patch (by that other person), I think it is faster to not >> do a strlen first. There are PowerPC architectures, where a strlen is a matter of a single instruction of the CPU. Quote: "PowerPC 405 and 440 instruction sets offer the powerful Determine Left-Most Zero Byte (DLMZB) instruction." That's propably hard to beat. So, if we really want to speed up these things, we should write code which helps the compiler get that optimized instructions for us - by improving the code of strlen() i.e. Reference: http://www-03.ibm.com/chips/power/powerpc/newsletter/sep2003/ppc_process_at_work2.html Greets, Clemens Koller _______________________________ R&D Imaging Devices Anagramm GmbH Rupert-Mayer-Str. 45/1 81379 Muenchen Germany http://www.anagramm-technology.com Phone: +49-89-741518-50 Fax: +49-89-741518-19