* limit cabq to 64 - in practice if this stays at ath_txbuf then
all buffers can be tied up by a very busy broadcast domain (eg ARP
storm, way too much MDNS/NETBIOS). It's been like this in the
freebsd-wifi-build AP project for the longest time.
* Now that I figured out the hilarity inherent in aggregate forming
and AR9380 EDMA work, change the per-node to 64 frames by default.
I'll do some more work to shorten the queue latency introduced when
doing data so TCP isn't so terrible, but it's now no longer /always/
tens of milliseconds of extra latency when doing active iperf tests.
Notes:
The reason for the extra latency is partly tx/rx taskqueue handling and
scheduling, and partly due to a lack of airtime/QoS awareness of per-node
traffic. Ideally we'd have different limits/priorities on the QoS/TID
levels per node so say, voice/video data got a better share of buffer
allocations over best effort/bulk data, but we currently don't implement
that. It's not /hard/ to do, I just need to do it.
Tested:
* AR9380 (STA), AR9580 (hostap) - both with the relevant changes.
TCP is now at around 180mbit with rate control and RTS protection
enabled. UDP stays at 355mbit at MCS23, no HT protection.
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