[GHC] #15938: Hadrian's recompilation check is extremely slow

[GHC]

#15938: Hadrian's recompilation check is extremely slow
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        Reporter:  bgamari           |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  high              |            Milestone:  8.8.1
       Component:  Build System      |              Version:  8.6.2
  (Hadrian)                          |
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by tdammers):

 Replying to [comment:10 bgamari]:
 > tdammers, how long did you let the build run for before aborting it?

 I made multiple attempts from a freshly git-cleaned tree, aborting at
 various points during library compilation. A rebuild after any of these
 started to produce output within under 2 seconds, and started to perform
 actual compilation within 3 seconds. There is a significant delay (on the
 order of ~5-7 seconds) on the "Configure package 'ghc'" step, but nowhere
 near the reported 15-45 seconds.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15938#comment:20>
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