At Tue Aug 4 22:17:54 UTC 2015 by Mike Perry mikeperry at torproject dot org
In some instances where I have not selected my guards manually, Tor Browser is unbearably slow. Like really, really painfully slow. The whole time. Until I reinstall it.
This makes me think that the performance of people who pick guards from the tail is much much worse than the performance of the top guards, and this property likely is acting as a deterrent to adoption.
Perhaps the guard-selection algorithm could be enhanced to consider some sort of distance/reachability metric generated by BWauths?
BWauths are continuously pairing relays for measurements, and perhaps metrics from that could be mapped to autonomous system numbers (from MaxMind) in a useful way without requiring tremendous effort? Matrix analysis comes to mind.
If one's guard is on the other side of the world, network latency and random congestion will hurt.
I've read some path selection research is under way with an eye toward reducing passive traffic correlation exposure--this seems like it would help performance in a similar way.