Hi Andrea > 1. Besides the results in Toke’s ICCRG presentation at IETF 91 in > November 2014 > (http://www.ietf.org/proceedings/91/slides/slides-91-iccrg-4.pdf), > where can I find other comprehensive comparisons of AQM > implementations for Linux (or any other non-simulated system that > handles real packets)?
The data underlying my experiments are available from here: http://www.cs.kau.se/tohojo/modern-aqms/ -- that page also has links to the test scripts used to run the experiments. The paper is still under submission, so can't link that, sadly, but I can share a copy with you privately if you are interested. > 2. In Toke’s slides, the fq_nocodel scheme appears to be never worse > than fq_codel (or any other AQM in those tests), except for the VoIP > delay plot of slide 12. Besides the Linux code, is there anywhere a > description of the fq_nocodel scheme? Well, fq_nocodel is basically the term I use for fq_codel configured so as to disable the CoDel algorithm (i.e. the target and/or interval is set to 100 seconds so the algorithm never triggers). As such, it doesn't have a description outside of my paper, but you can read the fq_codel draft and ignore everything it says about CoDel, I suppose :) Also, note that configuring fq_codel in this way in Linux is not optimal in terms of CPU use: it deliberate triggers the overflow drop mechanism, which does a linear search through all configured queues, eating up 4k of cache on every drop. If your test router is sufficiently CPU-over-provisioned (a modern x86 counts as this for <=1Gbit speeds) this doesn't affect performance, but I wouldn't recommend it on a tiny MIPS processor, for instance. (Oh, and this limitation is specific to the current implementation, and could easily be fixed if anyone wanted to; the overflow mechanism was meant as a backup, and so wasn't optimised like, say, the SFQ was). -Toke _______________________________________________ aqm mailing list [email protected] https://www.ietf.org/mailman/listinfo/aqm
