[tor-bugs] #22453 [Core Tor/Tor]: Relays should regularly do a larger bandwidth self-test

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#22453: Relays should regularly do a larger bandwidth self-test
-------------------------------------------------+-------------------------
 Reporter:  arma                                 |          Owner:  juga
     Type:  enhancement                          |         Status:
                                                 |  assigned
 Priority:  Medium                               |      Milestone:  Tor:
                                                 |  unspecified
Component:  Core Tor/Tor                         |        Version:
 Severity:  Normal                               |     Resolution:
 Keywords:  034-triage-20180328,                 |  Actual Points:
  034-removed-20180328, tor-bwauth               |
Parent ID:  #25925                               |         Points:
 Reviewer:                                       |        Sponsor:
-------------------------------------------------+-------------------------

Comment (by juga):

 Replying to [comment:3 arma]:
 > Replying to [comment:2 teor]:
 > > The reason it's set to 500kB is that's the circuit window (so it's not
 impacted by latency).
 >
 > No, the reason it's 500KB is because the threshold for Fast used to be
 50KB, and 50KB times 10 seconds = 500KB.
 >
 > Remember that we're sending the 500KB over 4 circuits, so it's well
 under the circuit window, per circuit.
 >
 > {{{
 > /** Number of testing circuits we want open before testing our
 bandwidth. */
 > #define NUM_PARALLEL_TESTING_CIRCS 4
 > }}}

 If i understand correctly the code [0]:

 {{{
   int num_cells = (int)(get_options()->BandwidthRate * 10 /
                         CELL_MAX_NETWORK_SIZE);
   int max_cells = num_cells < CIRCWINDOW_START ?
                     num_cells : CIRCWINDOW_START;
   int cells_per_circuit = max_cells / num_circs;
 }}}

 the 500KB were due to `CIRCWINDOW_START` (1000), the 1st line was not
 having effect.

 Do we want that the first test to send only 500KB (and then
 AuthDirGuardBWGuarantee*10 in the consecutives ones)?. `max_cells` then it
 just needs a condition.

 I'm not sure why there was `BandwidthRate` there, that's 1GB by default
 (bigger than AuthDirGuardBWGuarantee), and i think the 1st line was also
 missing to divide by the number of circuits (not only the cell size).

 The 10 in the first line is there because of the 10 seconds?

 [0]
 https://gitweb.torproject.org/tor.git/tree/src/feature/relay/selftest.c?h=release-0.3.5#n278

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/22453#comment:21>
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