Re: [Make-wifi-fast] [PATCH RFC v3 1/4] mac80211: Add TXQ scheduling API

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

Johannes Berg <johannes@sipsolutions.net> writes:

> On Mon, 2018-09-10 at 17:00 +0200, Toke Høiland-Jørgensen wrote:
>
>> > Do we even need end_schedule()? It's hard to pass multiple things to a
>> > single call (do you build a list?), so having
>> > 
>> > 	start_schedule(), get_txq(), return_txq()
>> > 
>> > would be sufficient?
>> 
>> Well, start_schedule() / end_schedule() would be needed if we are going
>> to add locking in mac80211?
>
> [...]
>
>> If we decide mac80211 needs to do locking to prevent two threads from
>> scheduling the same ac, that would also be needed for the hw-managed
>> case?
>
> Yes, good point.
>
>> > It seems like not? Basically it seems to me that in the hw-managed
>> > case all you need is may_tx()? And in fact, once you opt in you don't
>> > even really need *that* since mac80211 can just return NULL from
>> > get_skb()?
>> 
>> Yeah, we could just throttle in get_skb(); the separate call was to
>> avoid the overhead of the check for every packet. Typically, you'll pick
>> a TXQ, then dequeue multiple packets from it in succession; with a
>> separate call to may_tx(), you only do the check once, not for every
>> packet...
>
> Yeah, also a good point.
>
> Still, txq = get_txq(txq) doesn't feel right, so better to keep that
> separate I think.

Right, will do :)

-Toke