Re: [Make-wifi-fast] [PATCH v11 4/4] mac80211: Use Airtime-based Queue Limits (AQL) on packet dequeue

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

Justin Capella <justincapella@gmail.com> writes:

>> ieee80211_report_used_skb(). As an optimisation, we also subtract the
>> airtime on regular TX completion, zeroing out the value stored in the
>> packet afterwards, to avoid having to do an expensive lookup of the station
>> from the packet data on every packet.
>>
>> This patch does *not* include any mechanism to wake a throttled TXQ again,
>> on the assumption that this will happen anyway as a side effect of whatever
>> freed the skb (most commonly a TX completion).
>
> I recall a recent patch for ath10k sdio that disabled tx
> acknowledgement for performance gains and am wondering if that will be
> problematic? Presumably not since it would be caught at the dequeue,
> but thought I'd ask-- wondering what the effect of failed tx's or
> block acknowledgement is on this stuff I'll need to study the code
> some more
>
> https://lore.kernel.org/linux-wireless/0101016eb1903db0-ef7063b4-0f42-4a01-8886-327541e6c1a4-000000@us-west-2.amazonses.com/T/#t

It looks like that patch will just end up disabling AQL (because packets
will be immediately completed as far as mac80211 is concerned) and
replace it with whatever that credit-based scheme does? No idea how that
will impact latency; you should go ask the developers of that series! As
usual, the patch description only mentions throughput numbers :/

-Toke