[Cake] Query on ACK

[Toke Høiland-Jørgensen]

Dave Taht <dave.taht at gmail.com> writes:

> On Thu, May 7, 2020 at 11:36 PM Avakash bhat <avakash261 at gmail.com> wrote:
>>
>> Ok thanks so much for the clarifications.
>> That cleared it up quite a bit.
>
> I note that there was something really subtle that could have been
> done to improve cake's ack handling, and for all I know
> it actually happened in the final codebase.
>
> so, please, go forth and duplicate the existing implementation, and
> ignore me, cause looking at this hairy code gives me a
> headache.
>
> anyway, to try and describe what I thought I saw an interaction with
> the scheduler back in the day.
>
> The ack-filter runs, deleting all but one packet from the ack queue,
> and delivers that.
> the scheduler runs, serves a bunch of other flows, then returns to the
> ack queue, which has accumulated a couple more packets,
> the ack-filter runs, deleting all but one packet from the ack queue,
> and delivers that, but doesn't exhaust its qauntum

The ACK filter runs on enqueue, so if a queue has only ACKs in it, it
will never accumulate anything in the first place...

-Toke