From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1763706AbXK3Tfu (ORCPT ); Fri, 30 Nov 2007 14:35:50 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755382AbXK3Tfm (ORCPT ); Fri, 30 Nov 2007 14:35:42 -0500 Received: from smtpoutm.mac.com ([17.148.16.71]:62230 "EHLO smtpoutm.mac.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755196AbXK3Tfl (ORCPT ); Fri, 30 Nov 2007 14:35:41 -0500 In-Reply-To: <47505907.5030409@zytor.com> References: <474EAD18.6040408@stellatravel.co.uk> <20071130143445.GA2310@csclub.uwaterloo.ca> <53ADBDBF-9B65-441E-B867-D68DE48ABD64@mac.com> <47505907.5030409@zytor.com> Mime-Version: 1.0 (Apple Message framework v752.2) Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed Message-Id: <02B4DDE5-3D53-4BA5-BB79-52788CEBB9AF@mac.com> Cc: Lennart Sorensen , Ben Crowhurst , linux-kernel@vger.kernel.org Content-Transfer-Encoding: 7bit From: Kyle Moffett Subject: Re: Kernel Development & Objective-C Date: Fri, 30 Nov 2007 14:35:34 -0500 To: "H. Peter Anvin" X-Mailer: Apple Mail (2.752.2) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Nov 30, 2007, at 13:40:07, H. Peter Anvin wrote: > Kyle Moffett wrote: >> With that said, there is a significant performance penalty as all >> Objective-C method calls are looked up symbolically at runtime for >> every single call. > > GACK! > > At least C++ has vtables. In a tight loop there is a way to do a single symbolic lookup and just call directly through a function pointer, but typically it isn't necessary for GUI programs and the like. The flexibility of being able to dynamically add new methods to an existing class (at least for desktop user interfaces) significantly outweighs the performance cost. Any performance-sensitive code is typically written in straight C anyways. Cheers, Kyle Moffett