Subject: Re: [RFC][PATCH] mac80211: Use PID controller for TX rate control
From: Johannes Berg <johannes@sipsolutions.net>
To: Mattias Nissler <mattias.nissler@gmx.de>
Cc: Tomas Winkler <tomasw@gmail.com>,
	Stefano Brivio <stefano.brivio@polimi.it>,
	linux-wireless <linux-wireless@vger.kernel.org>,
	"John W. Linville" <linville@tuxdriver.com>
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Date: Tue, 04 Dec 2007 14:40:23 +0100
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> I already thought so. But the original "simple" algorithm is totally
> broken in most cases. Well, maybe except the cases perfect situation ->
> no tx failures -> full rate and bad situation -> lots of tx failures ->
> lowest rate. IMHO, we should just get rid of the old simple algorithm.

I tend to agree, but I guess we should rename it then and change the
default. Ultimately, we'll need to come up with some nl80211 API for
rate control algorithms that allows each algorithm to have different
parameters, similar to what tc(1) does for qdiscs.

If anybody's interested, here's what I'd do:

 (a) add new attributes "rate control algorithm" and "rate control
     algorithm attributes"
 (b) allow setting them with NL80211_CMD_SET_INTERFACE
 (c) the "rate control algorithm attributes" attribute is nested and
     contains per-algorithm information, the indexes in it are specific
     to each algorithm

This allows changing the algorithm as well as algorithm parameters.

johannes

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