[GHC] #15418: Performance drop 60 times on non-profiling binary

[GHC]

#15418: Performance drop 60 times on non-profiling binary
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        Reporter:  hth313            |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  high              |            Milestone:  8.6.1
       Component:  Runtime System    |              Version:  8.4.3
      Resolution:                    |             Keywords:
Operating System:  MacOS X           |         Architecture:  x86_64
 Type of failure:  Runtime           |  (amd64)
  performance bug                    |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:  #14414, #9599     |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by George):

 I think without a reduced test case with source this will be very hard to
 fix. It would be interesting to see if you can reproduce the issue in the
 related tickets above as I don't believe others have been able to. Others
 will probably have suggestions about what you can do on your side. You
 might want to take a look at the performance debugging section of
 https://ghc.haskell.org/trac/ghc/wiki/Debugging

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15418#comment:9>
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