[GHC] #13639: Skylighting package compilation is glacial

[GHC]

#13639: Skylighting package compilation is glacial
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        Reporter:  bgamari           |                Owner:  dfeuer
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:  8.4.1
       Component:  Compiler          |              Version:  8.0.1
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Compile-time      |  Unknown/Multiple
  performance bug                    |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by dfeuer):

 In a recent HEAD ( 4700baaf8f9bf3c44a53a595d840c7c14cfd6f98 ):

 The "nearly ten minutes" seems to be the "user" time in a parallel build,
 for which the real time is around 3 minutes. If cabal and GHC are each
 passed `-j1`, the user time drops to around five minutes. So one issue
 seems to be some inefficiency in parallel builds. Running single-threaded,
 I don't see any big difference between the time it takes to build the
 unprofiled and profiled versions (although of course building both takes
 about twice as long as building just the unprofiled). So I don't really
 think profiling has anything to do with the issue, at least for HEAD.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13639#comment:4>
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