Re: [Make-wifi-fast] [PATCH v8 0/2] Implement Airtime-based Queue Limit (AQL)

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

Johannes Berg <johannes@sipsolutions.net> writes:

> On Wed, 2019-12-04 at 04:47 +0000, Kalle Valo wrote:
>> 
>> > Overall, I think AQL and fq_codel works well, at least with ath10k.
>> > The current target value of 20 ms is a reasonable default.  It is
>> > relatively conservative that helps stations with weak signal to
>> > maintain stable throughput. Although, a debugfs entry that allows
>> > runtime adjustment of target value could be useful.
>> 
>> Why not make it configurable via nl80211? We should use debugfs only for
>> testing and debugging, not in production builds, and to me the use case
>> for this value sounds like more than just testing.
>
> On the other hand, what application/tool or even user would be able to
> set this correctly?

Well, it's not inconceivable that someone might write a tool to
dynamically tune this; we do allow it to be changed at the qdisc layer
after all.

But until such a time as someone does that, I agree that it's not
terribly likely such a knob is going to see much use. As Kan's results
show, for inter-flow latency (like what the separate ping in his test is
showing), the FQ part takes care of the latency, and what's left there
is the AQL buffering. So I'm a little bit "meh" about this; wouldn't
object to making it a knob, but don't think I'm going to spend the time
writing that patch myself :)

-Toke