Major Atheros issues with Ubiquiti SR9/XR9

[Geoffrey Mainland]

Hi,

I'm running 7-CURRENT on several ALIX 3c2 boards with SR9 radios and 
having major performance problems: throughput on TCP streams generated 
by iperf often falls to zero, and, depending on the HAL I use, I see 
ping latencies during one of these iperf transfers of up to more than a 
*minute*. I've tried both the 0.9.30.13 HAL and the new 0.10.5.6 HAL. I 
see this bad behavior with both, but the new HAL seems even worse.

I've documented my configuration and the test results at 
http://www.eecs.harvard.edu/~mainland/freebsd/sr9/. This includes the 
kernel configuration, dmesg output, pciconf output, rc.conf, athstats 
output, appropriate sysctl values, iperf/ping output generated by my 
driver script and some plots showing the problem.

We are trying to deploy a bunch of these nodes outdoors, using the 
900MHz radios as a backhaul, so the drop-outs I see with SR9s are a 
major problem for us. I've also run the same tests on Soekris nodes, 
used different SR9s, and also tried the new XR9s on the same ALIX 
boards---all with similar results. We also have a bunch of Wistrom CM9s 
which seem to work just fine.

Any idea what could be going on?

Thanks!
Geoff