From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751651AbbCORdL (ORCPT ); Sun, 15 Mar 2015 13:33:11 -0400 Received: from mx1.redhat.com ([209.132.183.28]:46774 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751450AbbCORdG (ORCPT ); Sun, 15 Mar 2015 13:33:06 -0400 Date: Sun, 15 Mar 2015 18:32:27 +0100 From: Jiri Olsa To: Arnaldo Carvalho de Melo Cc: Jiri Olsa , linux-kernel@vger.kernel.org, Corey Ashford , David Ahern , Ingo Molnar , Namhyung Kim , Paul Mackerras , Peter Zijlstra Subject: Re: [PATCH 01/15] perf build: Disable default check for libbabeltrace Message-ID: <20150315173227.GB14887@krava.brq.redhat.com> References: <1426064344-21737-1-git-send-email-jolsa@kernel.org> <1426064344-21737-2-git-send-email-jolsa@kernel.org> <20150313153621.GB3467@redhat.com> <20150313162011.GA21865@krava.brq.redhat.com> <20150313201935.GA4419@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20150313201935.GA4419@redhat.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Mar 13, 2015 at 05:19:35PM -0300, Arnaldo Carvalho de Melo wrote: SNIP > > but we need to add support for that first > > Thanks for explaining, that covers one of my peeves, i.e. the cset > comment wasn't clear, now it is a bit better, thanks! > > The other is for someone not interested in how the feature detection > works but then sees a warning about a feature not being available but > that feature doesn't appear on the followup summary of features that are > ON or OFF the build... > > So I think that when we think that some feature is experimental, for any > reason, for instance, because it is based on some feature that is not on > a released version of the library one needs to link against, to only > bother with trying to check if it is available and link against it if so > if it is _explicitely_ asked for. yep, but that'd be new feature, currently we check for everything and are able only to disable features via NO_* make variables > I.e. documentation should state that perf can have support for that > feature, but only if the user does: > > 1. installs the precisely described version that has what is needed. > > 2. Explicitely asks, in the make command line, for that feature. > > In the case at hand that would not even be a library release, but a > specific git commit on babeltrace's repo. > > That would be a speedup! ;-) > > - Arnaldo > > P.S. After all, we're not short on features, look at the ldd output... > Ok, I need to keep on merging the .config stuff, but even then, I guess > we need to have more of a dlopen approach to all those features, so that > one can install a package without dragging hell and its kitchen sink. yea, moving slowly towards to that step by step ;-) i rebased perf/build branch to your latest perf/core jirka