Message-ID: <20111206214446.GD1247@kroah.com>
Date:	Tue, 6 Dec 2011 13:44:46 -0800
From:	Greg KH <greg@...ah.com>
To:	Ingo Molnar <mingo@...e.hu>
Cc:	Peter Zijlstra <peterz@...radead.org>,
	Mathieu Desnoyers <mathieu.desnoyers@...icios.com>,
	devel@...verdev.osuosl.org, lttng-dev@...ts.lttng.org,
	linux-kernel@...r.kernel.org,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Andrew Morton <akpm@...ux-foundation.org>
Subject: Re: [PATCH 09/11] sched: export task_prio to GPL modules

On Mon, Dec 05, 2011 at 03:17:49PM +0100, Ingo Molnar wrote:
> 
> * Greg KH <greg@...ah.com> wrote:
> 
> > On Fri, Dec 02, 2011 at 12:07:10AM +0100, Peter Zijlstra wrote:
> > > On Thu, 2011-12-01 at 14:14 -0800, Greg KH wrote:
> > > > greg k-h
> > > 
> > > Greg, why are you merging this crap anyway? Aren't there enough tracer
> > > thingies around already?
> > 
> > I don't know, is there?
> > 
> > There's some reason the distros, and users, still use lttng, 
> > so I'm guessing that it fits the needs of quite a few people.
> 
> Same goes for a whole lot of other crap that distros are 
> carrying. Would we want to merge a different CPU scheduler or 
> the 4g:4g patch or a completely new networking stack into 
> drivers/staging/? I don't think so.

Distros have new CPU schedulers and are still dragging the 4g split
around?  A whole new networking stack would be interesting, and if
self-contained, possible :)

> I.e. putting LTTNG into drivers/staging/ will not really solve 
> anything - and in may in fact delay any sane technical 
> resolution:
> 
> There's a difference between a driver that has to go into 
> drivers/staging/ because nobody cares enough [and the driver 
> isnt high quality enough yet], and a core kernel feature that we 
> DO care about and which HAS BEEN REJECTED IN ITS FORM.

I didn't realize that lttng was rejected, when was that done?  I
couldn't find it in the archives anywhere.

That's why I took this.  It's a way for the code to get cleaned up, and
into "mergable" state, much easier, with more help than if it was
out-of-tree.  The fact that distros have been shipping and relying on it
for years shows that it is something that is needed, and it being
self-contained, makes it eligible for the staging tree.

> > That's why I'm merging it, if that the in-kernel stuff 
> > obsoletes lttng, great, let me, and the distros know.
> 
> I'm NAK-ing the LTTNG driver really, as it's a workaround for a 
> core kernel NAK.

Huh?

> Mathieu, please work with the tracing folks who DO care about 
> this stuff. It's not like there's a lack of interest in this 
> area, nor is there a lack of willingness to take patches. What 
> there is a lack of is your willingness to actually work on 
> getting something unified, integrated to users...
> 
> LTTNG has been going on for how many years? I havent seen many 
> steps towards actually *merging* its functionality - you insist 
> on doing your own random thing, which is different in random 
> ways. Yes, some of those random ways may in fact be better than 
> what we have upstream - would you be interested in filtering 
> those out and pushing them upstream? I certainly would like to 
> see that happen.
> 
> We want to pick the best features, and throw away current 
> upstream code in favor of superior out of tree code - this 
> concept of letting crap sit alongside each other when people do 
> care i cannot agree with.

Mathieu, a good explaination of what lttng has that the in-kernel
tracing and perf doesn't have would be a good place to start.

thanks,

greg k-h
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