[tor-bugs] #3835 [Torflow]: Scanner on bwscan vm is not making progress.

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#3835: Scanner on bwscan vm is not making progress.
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 Reporter:  mikeperry  |          Owner:  aagbsn
     Type:  defect     |         Status:  new   
 Priority:  major      |      Milestone:        
Component:  Torflow    |        Version:        
 Keywords:             |         Parent:        
   Points:             |   Actualpoints:        
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Changes (by mikeperry):

  * priority:  normal => major
 * cc: arma (added)


Comment:

 This could be caused by the new ratio grouping (#3444). moria is also not
 making progress on occasion, despite taking continued measurements and not
 crashing.

 Basically, grouping by ratio may cause higher churn in the slices, since
 it depends on both measured value and observed value. If the churn rate is
 faster than slice progress, no progress will be made.

 I also flipped FetchDirInfoEarly and FetchDirInfoExtraEarly in
 c86c1e134ae6d0b50b8b5344b1a25b01b4366302. Since they will cause consensus
 fetches every hour, this may be even worse.

 We could make the slices smaller to ensure completion, but I think nothing
 currently ensures that we will get at least one exit node in a slice.
 Perhaps we should still make them smaller, and also fix the selection to
 ensure exits anyway...

-- 
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/3835#comment:3>
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