Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756162AbZFXQtU (ORCPT ); Wed, 24 Jun 2009 12:49:20 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753054AbZFXQtM (ORCPT ); Wed, 24 Jun 2009 12:49:12 -0400 Received: from tomts36-srv.bellnexxia.net ([209.226.175.93]:45452 "EHLO tomts36-srv.bellnexxia.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751548AbZFXQtM (ORCPT ); Wed, 24 Jun 2009 12:49:12 -0400 X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: AtEEAGfxQUpMQWRX/2dsb2JhbACBUdMjhAsFgTQ Date: Wed, 24 Jun 2009 12:49:09 -0400 From: Mathieu Desnoyers To: "Frank Ch. Eigler" Cc: Ingo Molnar , Christoph Hellwig , Pierre-Marc Fournier , Tom Zanussi , karim@opersys.com, Michel Dagenais , ltt-dev@lists.casi.polymtl.ca, Lai Jiangshan , kosaki.motohiro@jp.fujitsu.com, linux-kernel@vger.kernel.org, Steven Rostedt , "Paul E. McKenney" , Robert Wisniewski Subject: Re: Dual-licensing LTTng, marker and tracepoints under GPLv2+/LGPLv2.1+ Message-ID: <20090624164909.GA20653@Krystal> References: <4A412702.80707@polymtl.ca> <20090623191128.GA19010@Krystal> <20090623191513.GA20253@Krystal> <20090624004356.GB28911@Krystal> <20090624083334.GB16850@elte.hu> <20090624141438.GA15420@Krystal> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline In-Reply-To: X-Editor: vi X-Info: http://krystal.dyndns.org:8080 X-Operating-System: Linux/2.6.21.3-grsec (i686) X-Uptime: 12:44:37 up 116 days, 13:10, 3 users, load average: 0.00, 0.03, 0.06 User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1936 Lines: 51 * Frank Ch. Eigler (fche@redhat.com) wrote: > Mathieu Desnoyers writes: > > > [...] The goal we pursue by dual-licensing with GPLv2/LGPLv2.1 is > > to permit instrumented applications to be themselves distributed > > under other license than GPL. [...] > > Is there some reason you can't just fork/copy off some earlier version > of these files over which you had sole authorship (if any)? > Actually, for LTTng, I own the copyright of almost everything we need. Most files written by others are mainly the debugfs interfaces done by Fujitsu. There is some derived work from RelayFS in ltt/ltt-relay-alloc.c and include/linux/ltt-relay.h, where getting IBM's approval would be good, but I think in the end this will end up being only a few tens of lines. > > > [...]The goal is to permit this library, which includes the > > tracepoints, markers and LTTng features, to be used by userspace > > applications and libraries so they can add static instrumentation > > (as we currently do in the kernel). [...] > > Just in case you're not aware, some API prior art for this is the > dtrace sdt.h widget (already supported by systemtap), and of course > it has no similarity to the various kernel tracing APIs. Yep, we're aware of this. However, last time I checked, dtrace SDT used a breakpoint even for their userspace tracing, which has a way too large performance overhead for our needs. Moreover, they support only very, very limited typing (0 to 5 u32). In this respect, tracepoints and markers are much more flexible. Thanks, Mathieu > > - FChE > -- Mathieu Desnoyers OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/