[GHC] #9234: Compiled code performance regression

[GHC]

#9234: Compiled code performance regression
---------------------------------+------------------------------------
        Reporter:  augustss      |            Owner:
            Type:  bug           |           Status:  new
        Priority:  low           |        Milestone:
       Component:  Compiler      |          Version:  7.8.2
      Resolution:                |         Keywords:
Operating System:  Windows       |     Architecture:  Unknown/Multiple
 Type of failure:  None/Unknown  |       Difficulty:  Unknown
       Test Case:                |       Blocked By:
        Blocking:                |  Related Tickets:
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Description changed by augustss:

Old description:

> Upgrading from ghc 7.2 to 7.8 has slowed down our main application
> noticeably.  This is with 32-bit Windows.
>
> Here's some 7.2 numbers:
> {{{
>   INIT    time    0.00s  (  0.00s elapsed)
>   MUT     time  287.78s  (290.41s elapsed)
>   GC      time   87.39s  ( 88.43s elapsed)
>   EXIT    time    0.00s  (  0.00s elapsed)
>   Total   time  375.63s  (378.86s elapsed)
> }}}
>
> And corresponding 7.8 numbers:
> {{{
>   INIT    time    0.00s  (  0.00s elapsed)
>   MUT     time  298.34s  (301.35s elapsed)
>   GC      time   88.16s  ( 89.27s elapsed)
>   EXIT    time    0.00s  (  0.00s elapsed)
>   Total   time  386.93s  (390.62s elapsed)
> }}}
>
> This is not unexpected since every ghc upgrade so far has slowed down out
> code; it's just following the trend we expect.

New description:

 Upgrading from ghc 7.6 to 7.8 has slowed down our main application
 noticeably.  This is with 32-bit Windows.

 Here's some 7.2 numbers:
 {{{
   INIT    time    0.00s  (  0.00s elapsed)
   MUT     time  287.78s  (290.41s elapsed)
   GC      time   87.39s  ( 88.43s elapsed)
   EXIT    time    0.00s  (  0.00s elapsed)
   Total   time  375.63s  (378.86s elapsed)
 }}}

 And corresponding 7.8 numbers:
 {{{
   INIT    time    0.00s  (  0.00s elapsed)
   MUT     time  298.34s  (301.35s elapsed)
   GC      time   88.16s  ( 89.27s elapsed)
   EXIT    time    0.00s  (  0.00s elapsed)
   Total   time  386.93s  (390.62s elapsed)
 }}}

 This is not unexpected since every ghc upgrade so far has slowed down out
 code; it's just following the trend we expect.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9234#comment:3>
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