Re: [RFC v2 2/4] mac80211: Add airtime accounting and scheduling to TXQs
From: Toke Høiland-Jørgensen <toke@toke.dk>
Date: 2018-08-29 14:30:12
Johannes Berg [off-list ref] writes:
On Wed, 2018-08-29 at 11:27 +0200, Toke H=C3=B8iland-J=C3=B8rgensen wrote:quoted
Hmm, the problem with a higher weight is that weight*quantum becomes the time each station is scheduled, so having a higher value means higher latency. This could be fixed by replacing the station weights with per-station quantums, but I felt that this was exposing an implementation detail in the API; if we ever change the enforcement mechanism to not be quantum-based (as may be necessary for MU-MIMO for instance), we'll have to convert values in the kernel. Whereas weights are a conceptual measure that is not tied to any particular implementation.Ok, but that's also an effect you should describe in the API for it.
What's the right place to put that? In the netlink header file?
Perhaps then it should just be fractional? i.e. 8.8 bits or so?, so the default would be 1.0 (0x0100) and then you could scale down to 0.5 (0x0080) etc?
Hmm, that's an interesting idea. I'll have to run some numbers to see how the precision holds up on various examples; but that would allow us to get rid of the quantum in the userspace API entirely, which is a good thing as far as I'm concerned!
quoted
For the drivers that get airtime as part of TX completion, sure; but as I understand it, at least ath10k gets airtime information in out of band status reports, so there would need to be a callback for that in any case...Hmm, ok, but perhaps then we should also tie those to the existing airtime things?
Eh? Tie what to which existing airtime things? -Toke