From: "Jean-Pierre Tosoni" <jp.tosoni@acksys.fr>
To: "'Felix Fietkau'" <nbd@openwrt.org>
Cc: <linux-wireless@vger.kernel.org>
References: <1372351227-25575-1-git-send-email-jp.tosoni@acksys.fr> <51CF3EC9.3000707@openwrt.org> <000001ce7728$18b07de0$4a1179a0$@acksys.fr> <51D2DAB9.4050002@openwrt.org>
In-Reply-To: <51D2DAB9.4050002@openwrt.org>
Subject: RE: [RFC v2] mac80211: Use libnl-configurable values for retry counts
Date: Tue, 2 Jul 2013 19:40:20 +0200
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Hi Felix,

Sorry to use your time again...

> But much more important than that is to not cause regressions for other
> people via aggressive packet dropping.

Agreed, but see below.

> If you put the code in minstrel (and minstrel_ht), it not only allows
> making a better tradeoff for retry handling, the code also doesn't have
> to be run for every single packet. You can run it during the rate
> control stats update.

OK, I'll have a look at that part now.

> 
> The reduction of retry attempts definitely needs to be balanced
> properly. Retries with max_prob_rate can be more important than retries
> with max_tp_rate, but there needs to be a minimum for each of those.

This leads to a question about regressions and backward compatibility:

Since minstrel can compute as much as 28 retries for a frame,
And since the (standard) default value for "short_frame_max_tx_count" is 7,

... there is no way I can enforce the configured value while keeping
minstrel counts by default !
The standard itself gives a very aggressive limit! Or am I mistaken about
the significance of this configuration parameter ?

Jean-Pierre