[metrics-bugs] #33399 [Metrics/Onionperf]: Measure static guard nodes with OnionPerf

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#33399: Measure static guard nodes with OnionPerf
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 Reporter:  acute                      |          Owner:  metrics-team
     Type:  enhancement                |         Status:  new
 Priority:  Medium                     |      Milestone:
Component:  Metrics/Onionperf          |        Version:
 Severity:  Normal                     |     Resolution:
 Keywords:  metrics-team-roadmap-2020  |  Actual Points:  0.1
Parent ID:  #33325                     |         Points:  4
 Reviewer:                             |        Sponsor:  Sponsor59-must
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Comment (by mikeperry):

 The function to reset buildtimeout is circuit_build_times_reset(). It is
 called when there are too many timeouts. It is not called via DROPGUARDS.

 We could make a DROPTIMEOUTS or similar command just like DROPGUARDS, that
 calls circuit_build_times_reset(), if that is simpler than removing the
 state file. I don't think DROPGUARDS should necessarily automatically
 reset CBT.

 It takes 100 circuits to learn a circuit build timeout. During this phase,
 circuits are launched roughly every 10 seconds. So it takes about 1000
 seconds to learn a timeout, at which point the BUILDTIMEOUT_SET COMPUTED
 event will be delivered again.

 During this time, fix-guards onionperf should not record perf measurements
 between RESET and SET (as per #33420).

 It makes sense that BUILDTIMEOUT_SET events other than COMPUTED are rare
 in onionperf production instances, because CBT only resets after many
 timeouts, and only SUSPENDs if TLS activity stops.

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/33399#comment:8>
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