Thanks for the information. I'd be interested in why you have chosen
PIE, e.g., instead of sfq-CoDel. Any pointers to evaluation
reports/results? Last time I saw a presentation on this it seemed
that CoDel was performing quite well.

I think this cablelabs report makes the argument for PIE:

http://www.cablelabs.com/downloads/pubs/Active_Queue_Management_Algorithms_DOCSIS_3_0.pdf

Mostly in that in the heavy traffic scenarios, PIE outperforms sfq_codel, and in general is a tad bit better than codel, with a simpler implementation (I think).  Although I think I take issue with the "heavy traffic" model, but I'm guessing (hoping) that it's based on surveys of customer traffic.  60-110 upstream flows seems like a lot.  But it's based around a heavy use of BitTorrent, so maybe that's reasonable for some people.

But in all other cases, sfq really blows the doors off of the others.

-Aaron