[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:
                                     |  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 osa1):

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

 If you previously linked with profiling libraries and runtime, relinking
 it with non-profiling libraries and runtime (or the other way around) can
 of course make a huge difference. In one case all library functions are
 profiled and you're using profiling RTS, in the other they're not profiled
 and the RTS has less overheads.

 I'm confused about what exactly you're doing. I understand that you have
 one program that you want to optimize, and you're trying different
 profiling settings. You have these three configurations:

 - Compiled without profiling and run
 - Compiled with profiling and run without profiling (i.e. no `+RTS -p`)
 - Compiled with profiling and run with profiling (`+RTS -p`)

 Can you report numbes for each of these?

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15418#comment:1>
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