Re: [Make-wifi-fast] [v3] ath9k: Switch to using mac80211 intermediate software queues.

["Toke Høiland-Jørgensen" <toke@toke.dk>]

Kalle Valo <kvalo@qca.qualcomm.com> writes:

> Toke Høiland-Jørgensen wrote:
>> This switches ath9k over to using the mac80211 intermediate software
>> queueing mechanism for data packets. It removes the queueing inside the
>> driver, except for the retry queue, and instead pulls from mac80211 when
>> a packet is needed. The retry queue is used to store a packet that was
>> pulled but can't be sent immediately.
>> 
>> The old code path in ath_tx_start that would queue packets has been
>> removed completely, as has the qlen limit tunables (since there's no
>> longer a queue in the driver to limit).
>> 
>> Based on Tim's original patch set, but reworked quite thoroughly.
>> 
>> Cc: Tim Shepard <shep@alum.mit.edu>
>> Cc: Felix Fietkau <nbd@nbd.name>
>> Signed-off-by: Toke Høiland-Jørgensen <toke@toke.dk>
>
> Nice work.

Thanks :)

> Because this is such a significant change, and to maximise testing
> time, I'm planning to queue this for 4.9 (so I would apply this to
> ath-next in 3-4 weeks after the merge window closes). But anyone who
> wants to test this can use master-pending branch from my ath.git tree
> (uses wireless-testing as the baseline). Sounds good?

Sounds good to me. I'm planning on backporting this and Michael's
mac80211 FQ-CoDel patches to 4.4 and post them for inclusion in LEDE.
Hopefully that will get it some more testing as well.

> Testing and review feedback very welcome!

My own evaluation results are here:
https://blog.tohojo.dk/2016/06/fixing-the-wifi-performance-anomaly-on-ath9k.html
-- I see aggregate throughput to multiple stations improve by a factor
of ~3 and latency under load decrease by a factor of ~10 now that we can
take advantage of the mac80211 FQ-CoDel patches.

-Toke