Recently Greg White and a few others at Cablelabs, along with Kathie Nichols, did an exhaustive simulation of a cable modem with a default amount of buffering, vs the new short queue option, vs codel, in a wide variety of scenarios.
The paper has just been released officially. http://www.cablelabs.com/downloads/pubs/PreliminaryStudyOfCoDelAQMinaDOCSISNetwork.pdf If you dig deeply into it, you'll see how really small queues can hurt performance (so don't do that), the effect of losing TCP syns in drop tail (don't saturate your buffers!), the effects of overbuffering at the driver level (hard to tell what reducing that will do in this sim), and a few other things like that. One problem with the web portion of the sim is that it doesn't simulate enough streams, and more importantly, it doesn't emulate the effects of DNS lookups. Still, it's interesting and more accurate than many others tests. I'm relatively happy with the voip test therein, although I structured the rrul equivalent to be much more difficult than the simulated one. And if you look at the (fairly few) places in the paper where codel doesn't shine, and think about where fq_codel compensates for that, you might go to bed with a glow on. I look forward to the followup paper. Thx cablelabs and kathie! -- Dave Täht Fixing bufferbloat with cerowrt: http://www.teklibre.com/cerowrt/subscribe.html _______________________________________________ Cerowrt-devel mailing list [email protected] https://lists.bufferbloat.net/listinfo/cerowrt-devel
