[GHC] #4801: Typechecker performance regression 6.12 -> 7.0.1

[GHC]

#4801: Typechecker performance regression 6.12 -> 7.0.1
--------------------------------------------+------------------------------
        Reporter:  simonmar                 |            Owner:  simonpj
            Type:  bug                      |           Status:  closed
        Priority:  high                     |        Milestone:  7.0.2
       Component:  Compiler (Type checker)  |          Version:  7.0.1
      Resolution:  fixed                    |         Keywords:
Operating System:  Unknown/Multiple         |     Architecture:
 Type of failure:  None/Unknown             |  Unknown/Multiple
       Test Case:  perf/compiler/T4801      |       Difficulty:  Unknown
        Blocking:                           |       Blocked By:
                                            |  Related Tickets:
--------------------------------------------+------------------------------
Changes (by goldfire):

 * difficulty:   => Unknown


Comment:

 The test T4801 is sometimes failing with "stat too good". I know Jan
 Stolarek was looking into this over the summer. Here are my numbers from
 MacOS 10.7.5 (x86_64):

 {{{
 max_bytes_used value is too high:
     Expected    max_bytes_used: 21657520 +/-5%
     Lower bound max_bytes_used: 20574644
     Upper bound max_bytes_used: 22740396
     Actual      max_bytes_used: 26596432
 peak_megabytes_allocated value is too high:
     Expected    peak_megabytes_allocated: 58 +/-1%
     Lower bound peak_megabytes_allocated: 57
     Upper bound peak_megabytes_allocated: 59
     Actual      peak_megabytes_allocated: 72
 bytes allocated value is too low:
 (If this is because you have improved GHC, please
 update the test so that GHC doesn't regress again)
     Expected    bytes allocated: 510938976 +/-5%
     Lower bound bytes allocated: 485392027
     Upper bound bytes allocated: 536485925
     Actual      bytes allocated: 458701280
 *** unexpected failure for T4801(normal)
 }}}

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/4801#comment:6>
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