[GHC] #8173: GHC uses nub

[GHC]

#8173: GHC uses nub
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        Reporter:  nh2               |            Owner:  leroux
            Type:  bug               |           Status:  new
        Priority:  normal            |        Milestone:
       Component:  Compiler          |          Version:  7.6.3
      Resolution:                    |         Keywords:
Operating System:  Unknown/Multiple  |     Architecture:  Unknown/Multiple
 Type of failure:  Compile-time      |       Difficulty:  Moderate (less
  performance bug                    |  than a day)
       Test Case:                    |       Blocked By:
        Blocking:                    |  Related Tickets:
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Comment (by simonpj):

 You don't want to compare the performance of the compiled nofib programs.
 After all, they should be bit-for-bit identical whether GHC internally
 uses `nub` or `nubOrd`!

 What you want to compare is the compile time!  The compile times are in
 the nofib logs, and `nofib-analyse` should compare them, but in the log
 you attach it says `(no modules compiled)`.  I don't know why.

 In any case, the differences in compile times will probably be mostly
 noise (a tiny difference in a large number, measured to only 0.1s
 precision or whatever).  You might instead want to focus on the amount of
 space allocated by GHC as it compiles.  That is at least precise and
 repeatable.  I'm not sure if the nofib infrastructure measures these.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8173#comment:8>
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