The attached patch attempts to deprioritize bulk ack flows in cake.

Once we start accumulating enough acks to filter out, and we start
filtering them out, the "sparse flow optimization" in cake will
start prioritizing the shorter queues. This patch attempts to stop
that, which should give more time for more acks to be eliminated,
and deprioritize bulk ack flows slightly in favor of other traffic
that needs less latency.

Interesting stats from testing would be to measure a change in
ack_drops between the two versions, and changes in the rate of
increase of tcp. The 50x1 settings would be the most dramatic test...

-- 

Dave Täht
CEO, TekLibre, LLC
http://www.teklibre.com
Tel: 1-669-226-2619