Date: Sat, 8 Dec 2007 12:17:25 +0100
From: Stefano Brivio <stefano.brivio@polimi.it>
To: Mattias Nissler <mattias.nissler@gmx.de>
Cc: Holger Schurig <hs4233@mail.mn-solutions.de>,
	linux-wireless@vger.kernel.org,
	Nick Kossifidis <mickflemm@gmail.com>,
	"John W. Linville" <linville@tuxdriver.com>,
	Johannes Berg <johannes@sipsolutions.net>
Subject: Re: rc80211-pid: some tuning test results
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On Sat, 08 Dec 2007 11:39:58 +0100
Mattias Nissler <mattias.nissler@gmx.de> wrote:

> Why wouldn't you let userspace set the raw parameters directly? The
> complicated scheme you propose prevents us to tell users/testers to
> "change the X parameter to see it gives better Y results". If you give
> access to the raw parameters, people can still tweak and tune them if
> the rate control fails for special situations (e.g. hardware that cannot
> report whether a frame was only retried or totally failed, special noise
> situations, whatever).
> 
> Furthermore, you can still have the simplified scheme by providing a
> userspace tool (maybe even add it to iw, once we have an interface) that
> takes the input, calculates the raw parameters as below and writes the
> results to the kernel.
> 
> Bottom line: This thing complicates the kernel, makes the thing less
> understandable for people who now what a PID controller is, complicates
> future tweaking and tuning of the (default) parameters and moreover
> could also be implemented in userspace. So my vote is against it.

I'm not so sure about this. I think that this is really specific to the
algorithm, so it looked like a natural choice to put this into the kernel.
But your points make a lot of sense. I should probably remove this from
here and send patches to iw.

> I've done a lot of code cleaning, maybe you want to base your patches on
> that. There's more to come, but I'll send them so you have something to
> start.

Me too I started to clean up the code, nevertheless if you send them it
will be useful. Thank you.


--
Ciao
Stefano