[Codel] [Bloat] [Cerowrt-devel] FQ_Codel lwn draft article review

[Eric Dumazet]

On Sun, 2012-12-02 at 23:15 +0100, Toke Høiland-Jørgensen wrote:
> Eric Dumazet <eric.dumazet at gmail.com> writes:
> 
> > If the next packet arrives while the bucket is still in old_flows,
> > we wont put the bucket in new_flow, its bucket have to wait its turn in
> > the RR list.
> 
> Right. So in order to stay in the new_flows list, the flow needs to be
> slow enough that no new data is added to it in the time it takes
> subsequent dequeue invocations to get back to it in the old_flows list?

I guess so. It must travel through the old_flows list from the tail to
the head (so each flows in old_flows must be serviced by one quantum),
to get the right to be declared as 'empty' and gain the honor to get
promoted to 'new_flows' next time a packet is enqueued.

If all flows are slow, but the queue can still build up, because there
are too many flows for the possible bandwidth, than all flows are
actually considered as thick, as if we had a single RR queue. (the
old_flows).