From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758200Ab2GLGPO (ORCPT ); Thu, 12 Jul 2012 02:15:14 -0400 Received: from ozlabs.org ([203.10.76.45]:37045 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756975Ab2GLGPK (ORCPT ); Thu, 12 Jul 2012 02:15:10 -0400 From: Rusty Russell To: Catalin Marinas Cc: Arnd Bergmann , Alan Cox , Ingo Molnar , Olof Johansson , "linux-kernel\@vger.kernel.org" , Linus Torvalds , Russell King , Andrew Morton Subject: Re: [PATCH 00/36] AArch64 Linux kernel port In-Reply-To: <20120711105335.GD22437@arm.com> References: <1341608777-12982-1-git-send-email-catalin.marinas@arm.com> <20120710101018.GE15120@arm.com> <20120710163358.6ae4a576@pyramind.ukuu.org.uk> <201207101652.18401.arnd@arndb.de> <877guarhpi.fsf@rustcorp.com.au> <20120711105335.GD22437@arm.com> User-Agent: Notmuch/0.12 (http://notmuchmail.org) Emacs/23.3.1 (i686-pc-linux-gnu) Date: Thu, 12 Jul 2012 11:38:08 +0930 Message-ID: <87y5mppw8n.fsf@rustcorp.com.au> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 11 Jul 2012 11:53:35 +0100, Catalin Marinas wrote: > Hi Rusty, Hi Catalin, This is fun! > On Wed, Jul 11, 2012 at 06:26:49AM +0100, Rusty Russell wrote: > > I know it's a crazy idea, but why don't we try some actual analysis? > > This kind of analysis is not relevant. It's not like you can use a tool > to just mix the lines from one file with another and get a merged port. Whether a tool or human would do it, using some methodology to measure similarity of two ports seems more informative than relying on the gut feel of developers. > The tool claims unicore32 shares 57% with arch/arm. It gets confused in > the same way because unicore32 started with the ARM port as the code > base. Do we want it merged with arch/arm based on hashmatch? It doesn't "get confused"; it means exactly what it says. Sure, it's rough, but it's unbiased. And it indicates that arch/aarch64 is as related to arch/arm as arch/unicore32 is, ie. no more than expected from an arm-derived port. (I actually get 56% for unicore32, 52% for aarch64). Thus I consider my previous position proven incorrect: aarch64 should be its own tree. > This tool also shows that pretty much most of the atomic.h file in > AArch64 is the same with AArch32. That's completely wrong as the > assembly syntax is different for the two architectures (even the asm > comment has changed from @ to //). That's a file that can never be > shared. That's why I subtracted a randomly-chosen other arch (sparc) to try to eliminate such boilerplate similarities. Cheers, Rusty.