Thus spake Sebastian Urbach (sebastian@urbach.org):
Yeah, I agree. I think that it's now clear that both the variance and the mean of the torperf graphs are way above norm, and we don't have much other explaination for it other than the feedback experiment not working. The question is why?
I don't want to be the guy who posts always the bad news ...
I can happily report that the load, since your last mail, increased rapidly to max values and also the performance from the metrics page seems to be increasing very well right now.
If you want to take a look for yourself:
https://metrics.torproject.org/routerdetail.html?fingerprint=0aff5440ae93f2e...
Coincidink ;-) ?
I dont think so ...
I hope that this will relieve a little bit pressure from you, Mike.
Just to be sure, I decided to shut off the experiment on Sunday at 3pm US Pacific time anyways. It looks like the performance has in fact gotten worse since then.
Does this mean the feedback was definitely working? Who the hell knows. But it does seem clear that the transition between the two states is definitely a rocky one that requires patience and repeated trials to sniff out.
I am going to leave it disabled for another week, just to see how it recovers, then turn it back on again, possibly with the addition of https://trac.torproject.org/projects/tor/ticket/4730 if I get a hot minute, but possibly without it, just to watch the transition again.
Robert Ransom is quite insistent on the need for this as well: https://trac.torproject.org/projects/tor/ticket/4708, but that system doesn't really need me to build it, as it can be done independent of the bwauths. I also think #4730 is more likely to capture the problem we were seeing with fast nodes being fast only sometimes, and it will be way less work.
Thanks for bearing with me, but we still might have a ways to go before we really get to the bottom of this one.
I will keep you posted.