Set up a few new torperfs with fixed sets of entry guards
In theory, the results of legacy/trac#1918 (moved) (annotate torperf fetches by path) should let us simulate the expected performance of Tor users that use various combinations of guard nodes: just grab all the requests that use the guards you're simulating using, and make a torperf graph out of just those requests.
The problem is that the CBT feature will alter Tor's circuit build timeout based on the average build times of all nodes, not just the guards we're pretending we used, so we won't be able to capture the whole picture.
How different will the results be? To get some intuition, we should run several torperf install with cbt enabled and various sets of guards. Then when we have enough annotated torperf runs, we'll be able to compare the simulated results with the actual results, and make some decisions about what went wrong.
So the first question is: what combinations of guards should we try using? Mike, do you have any good guesses here?