[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
           Keywords:                    |  Operating System:  MacOS X
       Architecture:  Unknown/Multiple  |   Type of failure:  None/Unknown
          Test Case:                    |        Blocked By:
           Blocking:                    |   Related Tickets:
Differential Rev(s):                    |         Wiki Page:
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 I have a rather large application that I have spent quite some time on
 tuning it as performance is just too bad. I have come to a point where the
 profiler reports about 14 seconds on a particular example, which is about
 5x slower than I would like to see.

 However, building the same binary without profiling ability results in
 that the example takes 14 _minutes_. If I just touch a file and build with
 profiling information, but not giving it any profiling related RTS
 options, it takes about 30 seconds (not 14 seconds, but that is probably
 due to profiling overhead being there).

 How can performance drop 60x when I basically just relink it?

 From what I can see using "top" and memory profiling, memory consumption
 is quite stable over time.

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