From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752356Ab3JHBl1 (ORCPT ); Mon, 7 Oct 2013 21:41:27 -0400 Received: from mail-pa0-f50.google.com ([209.85.220.50]:34272 "EHLO mail-pa0-f50.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751586Ab3JHBl0 (ORCPT ); Mon, 7 Oct 2013 21:41:26 -0400 Message-ID: <525362C1.4010402@gmail.com> Date: Mon, 07 Oct 2013 19:41:21 -0600 From: David Ahern User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.8; rv:17.0) Gecko/20130801 Thunderbird/17.0.8 MIME-Version: 1.0 To: Ingo Molnar , Jiri Olsa CC: linux-kernel@vger.kernel.org, Peter Zijlstra , Arnaldo Carvalho de Melo , Namhyung Kim Subject: Re: [RFC PATCH 00/50] tools/perf: Speed up the build system References: <1381147003-2574-1-git-send-email-mingo@kernel.org> <5252BCB4.5030802@gmail.com> <20131007141100.GA21873@gmail.com> <5252D4DB.30302@gmail.com> <20131007164156.GA12790@gmail.com> In-Reply-To: <20131007164156.GA12790@gmail.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10/7/13 10:41 AM, Ingo Molnar wrote: > > * David Ahern wrote: > >> I also noticed that the dwarf test is still run even with the NO_DWARF >> option passed in: >> >> [daahern@nxos-vdc-dev1 perf]$ make O=/tmp/junk LDFLAGS=-static >> NO_DWARF=1 -j 4 >> BUILD: Doing 'make -j16' parallel build >> >> Auto-detecting system features: >> >> ... backtrace: [ on ] >> ... dwarf: [ on ] >> ... fortify-source: [ on ] >> >> Note the dwarf test shows 'on'. > > Hm, yes. > > This is just the print-out though - the actual feature logic should still > follow the NO_DWARF=1 setting (modulo bugs). > > So I'm wondering, should we solve this by adding extra logic linking the > feature flags with their legacy names. It would get unwieldy rather > quickly I think. yes. > Another solution would be to introduce a new method to disable features, > via something like: > > make FEATURE_dwarf=0 > > Where the pattern would follow the auto-detected naming. This would > simplify the printout logic and would simplify the feature support / flags > decision tree as well. > > Furthermore, it would unify the various flags we have today, which is > rather mixed: for example there's NO_DWARF which is a name that shows > negated logic, but there's also HAVE_CPLUS_DEMANGLE_SUPPORT is is a name > with positive logic. We'd have one uniform naming scheme permeating the > whole build system. The Kconfig series converts all of the NO_XXXXX to CONFIG_XXXXX. I'd like to see that because it mirrors kernel configs and is a stepping stone to kconf integration. If the NO_XXXX takes precedence over the autoprobe detection then the user gets what is asked, so I guess we can leave it as is for now. > > And that brings in your [K]config patches: which would make sense in that > context as well, as they'd allow the permanent configuration of features > with 3 states for each feature flag: > > off > auto-detect > on > > Your scheme I think makes a lot of sense on top of my bits. Packagers > would likely want to use a .config to build perf, most users would likely > be fine with a default of everything on auto-detect. Specialized users > would want to use their own .config's. Yes. This series helps with the auto-probing config option. Jiri has done quite a bit in this direction as well. Once this set goes in I'll see if I can find some time to revisit the kconf stuff - unless Jiri beats me to it. We have been overlapping on a few features. ;-) David