Re: [Make-wifi-fast] Support for airtime scheduling using ath10k

[Miguel Catalan Cid <miguel.catalan@i2cat.net>]

El mar., 23 jun. 2020 a las 11:35, Toke Høiland-Jørgensen
(<toke@redhat.com>) escribió:
>
> Miguel Catalan Cid <miguel.catalan@i2cat.net> writes:
>
> > Hi,
> >
> > we are trying to apply different airtime weights to different stations in
> > order to have some prioritization among connected stations. While this is
> > working pretty well with ath9k, with ath10k we always obtain a fair
> > distribution of the airtime (i.e. 50%-50% in the case of two stations),
> > regardless of the airtime weight specified.
> >
> > E.g. STA1:
> > RX: 0 us
> > TX: 2295610622 us
> >
> > *Weight: 200*Deficit: VO: 256 us VI: 256 us BE: 34 us BK: 256 us
> >
> > E.g. STA2:
> > RX: 0 us
> > TX: 162597077 us
>
> 2295610622/162597077 ~= 14
>
> which is not *too* far from the 20/1 ratio you've configured? Does the
> ratio change at all when you change the weights (i.e., if they are
> equal, do you get closer to a 50/50 split?).
>
> Do the two stations have roughly the same signal strength / rate?

In this case I started the STA1 a bit earlier, so it had a higher
airtime aggregate. Indeed, to compare the airtime share, I was
continuously monitoring the "airtime rate" (i.e. the difference
between Airtime(now) and Airtime (now-4s)) and the results of both
STAs were the same (i.e. 50/50 split) independently of the weight
being used. But when using ath9k the same test runs perfectly
according to the weights.

>
> > *Weight: 10*Deficit: VO: 256 us VI: 256 us BE: 9 us BK: 256 us
> >
> > We are using Compex WLE650V5-18A cards.
> >
> > So, does ath10k support airtime scheduling? In such a case, do we need
> > specific Wi-Fi cards?
>
> It should. My guess would be that maybe you're not getting enough
> backpressure for the scheduler to actually enforce things correctly. You
> could try to look at the TXQ output and see if you actually have any
> drops ('iw dev wlan0 station dump -v' and look at the drops/marks
> columns).

ok, i will check!

>
> What kernel version are you running? If it's not new enough to have AQL,
> that might help moving the backlog to where the scheduler can do more
> with it.

Kernel 5.5.5.

>
> -Toke
>

Thanks for your reply.
Miguel.
--
Miguel Catalán Cid, PhD

Mobile Wireless Internet Group (MWI)
i2CAT Foundation, Barcelona, Spain
http://www.i2cat.net/