K 10
svn:author
V 6
adrian
K 8
svn:date
V 27
2017-01-23T04:47:38.713964Z
K 7
svn:log
V 1283
[ath] modify cabq and per-node packet usage limits.

* 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.

END