[tor-bugs] #18122 [Tor Browser]: Show prefetched new Tor circuit

[Tor Bug Tracker & Wiki]

#18122: Show prefetched new Tor circuit
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 Reporter:  bugzilla                             |          Owner:  tbb-
     Type:  enhancement                          |  team
 Priority:  Medium                               |         Status:
Component:  Tor Browser                          |  reopened
 Severity:  Normal                               |      Milestone:
 Keywords:  tbb-circuit-display, tbb-usability,  |        Version:
  tbb-performance                                |     Resolution:
Parent ID:                                       |  Actual Points:
  Sponsor:                                       |         Points:
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Comment (by cypherpunks):

 It is rare that circuit creation is slow. What usually happens is that the
 network connection times out after Tor attaches the stream to a circuit
 (the timeout is normally 10s). If that happens, Tor will retry with a new
 circuit.

 Some exit nodes appear to be blackholed by some destinations and don't
 receive any network replies. In this case you will get the timeouts.

 I often monitor timestamped Tor control STREAM and CIRC events, so I know
 where the delay is.

 Your UI suggestions in comment 2 don't make much sense. Idle prebuilt
 circuits are assigned opportunistically and may be used by an existing tab
 or some other application or Tor may have to create a new one if the exit
 relay doesn't support the target port.

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/18122#comment:4>
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