[Bloat] Steam In Home Streaming on ath9k wifi

[Toke Høiland-Jørgensen]

Caleb Cushing <xenoterracide at gmail.com> writes:

>>
>>
>> So this is two computers talking to each other over WiFi? What
>> chipsets/drivers are they using for WiFi? It may very well be that what
>> you're seeing is hickups in the WiFi connection at the computer, not at
>> the router. In which case there's nothing you can do on the router to
>> fix it.
>>
>
> sure possible, can't say it's not, I did manage to find a channel that
> only I'm on in the 5 ghz range and all machines are within 2 meters of
> the AP. But of course it's wifi so, no real guarantees.
>
> Both computers are running windows 10. Server is running a qualcomm
> device says it's using the killer wireless n/a/c version 4.0.2.26
> (fishy, I know killer wireless is sort of it's own qos, I think I've
> effectively disabled it though). Client is running an Intel Dual Band
> wireless AC 8260, driver 19.71.1.1.

Right, no idea how Windows drivers behave. But odds are that the
bottleneck is at the client, since that often has worse antennas than
the AP. If you're in a position to take packet captures at both clients
and AP you may be able to figure it out; may require tightly
synchronised clocks to do properly, though.

How do you see the latency spikes? An end-to-end ping? You could try
pinging the AP from both clients and see which one sees the latency
spike...

>> Another possibility is that it's an occasional signal drop that causes
>> excessive retries (either at the router or the AP). We have not gotten
>> around to limiting the retries in the drivers yet, so that can cause
>> quite a bit of very intermittent head of line blocking as well.
>>
> could also be, do those retries happen when it's udp? 'cause I think
> steam homestreaming is basically all udp, maybe the packets are just
> getting dropped?

Yeah, those are link-layer retransmissions. The ath9k driver sometimes
retries individual packets up to 30 times, which is obviously way too
much...

-Toke