Message-ID: <20110105234021.GC1692@nowhere>
Date:	Thu, 6 Jan 2011 00:40:25 +0100
From:	Frederic Weisbecker <fweisbec@...il.com>
To:	Mathieu Desnoyers <mathieu.desnoyers@...icios.com>
Cc:	LKML <linux-kernel@...r.kernel.org>,
	Steven Rostedt <rostedt@...dmis.org>,
	Ingo Molnar <mingo@...e.hu>,
	Thomas Gleixner <tglx@...utronix.de>
Subject: Re: [RFC patch 3/5] ftrace trace event add missing semicolumn

On Wed, Jan 05, 2011 at 02:56:12PM -0500, Mathieu Desnoyers wrote:
> * Frederic Weisbecker (fweisbec@...il.com) wrote:
> [...]
> > Looks good!
> > 
> > I might be missing corner things but it seems this would reduce the code
> > footprint (one function less) and turn more rw into ro datas.
> > 
> > So it seems to be a very valuable reason to change the semicolon requirement
> > all over the place.
> > 
> > If you come up with this feature along the massive semicolon requirement
> > change, we will probably happily apply the whole.
> > 
> > But coming with only the semicolon change is more like an empty shell.
> 
> My proposal here is to incrementally improve the tracing code, starting by
> cleaning up what is already there. I cannot do this if you keep asking me for
> larger changes to both Ftrace and Perf before any of the prerequisite cleanups
> can make their way in.
> 
> In this thread, I demonstrated that the TRACE_EVENT cleanup I proposed opens a
> lot of code/data size reduction cleanups for Ftrace and Perf. But let's get the
> cleanup in there first (it does not break the current way Ftrace and Perf are
> working), and once all the code-base has moved to the semicolumn-less semantic,
> then we can start improving Ftrace and Perf.

Don't be suprised of my reaction. The way the things were presented was:

1) A patch with an meaningless changelog, absolutely no idea why that new
semicolon is useful for.

2) Me asking you why

3) You explaining me it's actually part of a much bigger cleanup for
a goal almost completely useless

4) Me has a hard time considering the big cleanup useful as is. Expressing
my worries.

5) You detailing much more the semicolon symptoms, and finally dropping an
evasive reason to do this cleanup, collapsed in the obsure notion of "arrays
of event"..

6) Me still puzzled by the big cleanup just for the sake of unnoticeable
files.i pollution cleanup. But I try to give some chance by asking to
expand the "arrays of event" idea.

7) You explaining me something that looks like a meaningful, useful reason for
the big cleanup, but as a possibility. You propose me that I reuse the Lttng code that
you pick as an example, not suggesting you're planing to handle that part.

8) Me: ok for the big cleanup then, if you plan to also handle the useful change
you detailed, because otherwise it's meaningless.

See? That meaningful reason came so late in the discussion, and was proposed
so much under the angle of the possibility rather than something you plan
that I just thought you would just drop that empty shell and run away.

Hence my worries.

But if you plan to do the thing incrementally, this is also perfectly ok.

And you know what, may be you won't eventually have the time to complete
with the useful part. And may be someone else will handle that part.
Whatever, it's ok. We don't always finish everything.
But at least fill your changelogs with the useful longterm goal so that we
know we are going somewhere with this.


> As we say in French, "il ne faut pas mettre la charrue devant les boeufs"
> (roughly: don't put the cart before the horse)

As we say in French, "oui mais il a fallu te tirer les vers du nez"
(roughly: right, but still I had to worm it out of you)
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