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From:   Toke =?utf-8?Q?H=C3=B8iland-J=C3=B8rgensen?= <toke@redhat.com>
To:     Miguel Catalan Cid <miguel.catalan@i2cat.net>,
        make-wifi-fast@lists.bufferbloat.net,
        linux-wireless@vger.kernel.org
Subject: Re: [Make-wifi-fast] Support for airtime scheduling using ath10k
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Date:   Tue, 23 Jun 2020 11:35:29 +0200
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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?

> *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).

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.

-Toke