From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750827AbWHYKPP (ORCPT ); Fri, 25 Aug 2006 06:15:15 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750913AbWHYKPP (ORCPT ); Fri, 25 Aug 2006 06:15:15 -0400 Received: from pentafluge.infradead.org ([213.146.154.40]:7644 "EHLO pentafluge.infradead.org") by vger.kernel.org with ESMTP id S1750827AbWHYKPO (ORCPT ); Fri, 25 Aug 2006 06:15:14 -0400 Subject: Re: [PATCH 0/4] Compile kernel with -fwhole-program --combine From: David Woodhouse To: Sam Ravnborg Cc: Jan Engelhardt , linux-kernel@vger.kernel.org In-Reply-To: <20060825072654.GC30453@uranus.ravnborg.org> References: <1156429585.3012.58.camel@pmac.infradead.org> <1156433068.3012.115.camel@pmac.infradead.org> <1156439110.3012.147.camel@pmac.infradead.org> <20060825072654.GC30453@uranus.ravnborg.org> Content-Type: text/plain; charset=UTF-8 Date: Fri, 25 Aug 2006 11:14:53 +0100 Message-Id: <1156500893.2984.70.camel@pmac.infradead.org> Mime-Version: 1.0 X-Mailer: Evolution 2.6.3 (2.6.3-1.fc5.5.dwmw2.1) Content-Transfer-Encoding: 8bit X-SRS-Rewrite: SMTP reverse-path rewritten from by pentafluge.infradead.org See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 2006-08-25 at 09:26 +0200, Sam Ravnborg wrote: > And this discussion is btw. mood. If the general opinion is that we shall > include the -combine support all the kbuild infrastructure will anyway > be redone. > There are several small things that are not addressed in todays > implementation and that will be fixed one way or the other. There's a few _big_ things that aren't addressed in my makefile hack either. It's very much a proof of concept. However, if we limit the use of --combine to files within the same directory, the modifications to the kbuild infrastructure shouldn't be too intrusive. I strongly suspect that files within the same directory are where the majority of the benefit is anyway. Whole-kernel optimisation is likely to be prohibitively expensive, and can wait for LTO¹. -- dwmw2 ¹ http://www.gelato.org/pdf/apr2006/gelato_ICE06apr_lto_mitchell_codesourcery.pdf