From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753992Ab3IMRPh (ORCPT ); Fri, 13 Sep 2013 13:15:37 -0400 Received: from mail-vb0-f52.google.com ([209.85.212.52]:43265 "EHLO mail-vb0-f52.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752036Ab3IMRPe (ORCPT ); Fri, 13 Sep 2013 13:15:34 -0400 MIME-Version: 1.0 In-Reply-To: <20130913094555.GA11611@gmail.com> References: <20130912184341.GA11400@ghostprotocols.net> <52321CE4.1080804@gmail.com> <20130912201855.GC32644@gmail.com> <20130912203831.GD11400@ghostprotocols.net> <20130912204618.GA3262@gmail.com> <52322D81.5090708@gmail.com> <20130912211846.GA7890@gmail.com> <52323BE4.5080100@gmail.com> <20130913050927.GA8634@gmail.com> <20130913094555.GA11611@gmail.com> Date: Fri, 13 Sep 2013 19:15:33 +0200 Message-ID: Subject: Re: [GIT PULL] perf fixes From: Jean Pihet To: Ingo Molnar Cc: David Ahern , Arnaldo Carvalho de Melo , Linus Torvalds , Linux Kernel Mailing List , Peter Zijlstra , Thomas Gleixner , Andrew Morton Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 13 September 2013 11:45, Ingo Molnar wrote: > > * Jean Pihet wrote: > >> Hi, >> >> On 13 September 2013 07:09, Ingo Molnar wrote: >> > >> > * David Ahern wrote: >> > >> >> > By default a simple 'make' should build perf to the maximum extent >> >> > possible, with no other input required from the user - with warnings >> >> > displayed as package install suggestions. >> >> >> >> By default there is no config. Autoprobing generates a first one or a >> >> user can specify a defconfig. >> > >> > This could work if there's not two but three states for individual >> > features: >> > >> > - autoprobe >> > - on >> > - off >> > >> > and if autoprobe, if a system feature has been probed successfully, >> > automatically turned 'autoprobe' entries into 'on'. >> > >> > That would give us the best of all worlds - autodetection, configurability >> > and caching: >> > >> > - initial user types 'make' and gets a .config that has almost all >> > entries 'on', a few 'autoprobe'. >> > >> > - once the user installs a dependency, the corresponding .config entry >> > turns into 'on'. >> > >> > - the regular user or developers would have libraries that turn all >> > entries in the .config to 'on'. >> > >> > - if a user is genuinely uninterested in a feature, he can mark it 'off', >> > which would then stay off permanently. This could also be used by >> > embedded/specialized builds. >> > >> > - other specialized users, like distro builds, could use a .config with >> > all entries 'on' and could enforce the presence of all dependencies for >> > a successful build. [We could add 'make allyesconfig' to help that.] >> >> Is there a way to detect the presence of a dependency and _also_ check >> its version? Some new features are depending on a recent version of a >> library, e.g. dwarf unwinding depends on libunwind >= 1.1 (cf. >> http://www.spinics.net/lists/kernel/msg1598951.html). > > Yeah, see the testcases in tools/perf/config/feature-tests.mak, they > typically include the latest library API usages, which will fail on older > versions. Ok! I just sent a patch to feature-tests.mak for the newly added dwarf unwinding feature ('perf tools: Check libunwind for availability of dwarf parsing feature'). Thanks, Jean > > That kind of 'does it actually work?' test is a lot more robust than > explicit version checks, and combined with caching it should be fast and > parallelizable as well. (One of the problems of the current simple > implementation of the feature tests is that they are 20 serial tests with > no parallelization.) > > Thanks, > > Ingo