[tor-bugs] #27337 [Core Tor/sbws]: Round relay bandwidths in bandwidth files

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#27337: Round relay bandwidths in bandwidth files
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     Reporter:  teor           |      Owner:  (none)
         Type:  defect         |     Status:  new
     Priority:  Medium         |  Milestone:  sbws 1.0 (MVP must)
    Component:  Core Tor/sbws  |    Version:
     Severity:  Normal         |   Keywords:
Actual Points:                 |  Parent ID:
       Points:                 |   Reviewer:
      Sponsor:                 |
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 Torflow rounds raw bandwidths to 3 significant figures, and increases 0
 bandwidths to 1:

 https://gitweb.torproject.org/torflow.git/tree/NetworkScanners/BwAuthority/aggregate.py#n62

 Rounding

 sbws must round to 3 (or fewer) significant figures, so that consensus
 diffs are still efficient.

 I suggest 2 significant figures, because the largest error is 5% at
 1.5*10^n^ (for example: (105-100)/100 = 5%).

 Bandwidth authorities already vary from each other by 25-50%:
 https://trac.torproject.org/projects/tor/ticket/25459#comment:5

 And network load varies each day (from what I remember, my guards and
 exits used to vary by at least 10% every day).

 Avoiding Zeroes

 I think sbws should also increase 0 bandwidths to 1.

 We also have to update the spec, I'll open a child ticket.

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/27337>
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