[GHC] #9315: Weird change in allocation numbers of T9203

[GHC]

#9315: Weird change in allocation numbers of T9203
-------------------------------------+-------------------------------------
              Reporter:  nomeata     |             Owner:  simonmar
                  Type:  bug         |            Status:  new
              Priority:  normal      |         Milestone:
             Component:  Runtime     |           Version:  7.9
  System                             |          Keywords:
            Resolution:              |  Operating System:  Unknown/Multiple
Differential Revisions:              |   Type of failure:  None/Unknown
          Architecture:              |         Test Case:
  Unknown/Multiple                   |          Blocking:
            Difficulty:  Unknown     |
            Blocked By:              |
       Related Tickets:              |
-------------------------------------+-------------------------------------

Comment (by jrp):

 Running with the validate settings (ie, running validate) I get all the
 performance tests to pass other than:


 {{{
 =====> T4801(normal) 1987 of 4045 [0, 0, 0]
 cd ./perf/compiler && '/Users/jrp/Projects/haskell/ghc/inplace/bin/ghc-
 stage2' -fforce-recomp -dno-debug-output -no-user-package-db -rtsopts
 -fno-ghci-history -c T4801.hs   +RTS -V0 -tT4801.comp.stats --machine-
 readable -RTS -static >T4801.comp.stderr 2>&1
 max_bytes_used value is too low:
 (If this is because you have improved GHC, please
 update the test so that GHC doesn't regress again)
     Expected    T4801(normal) max_bytes_used: 25145320 +/-5%
     Lower bound T4801(normal) max_bytes_used: 23888054
     Upper bound T4801(normal) max_bytes_used: 26402586
     Actual      T4801(normal) max_bytes_used: 23720120
     Deviation   T4801(normal) max_bytes_used:     -5.7 %
 peak_megabytes_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    T4801(normal) peak_megabytes_allocated: 70 +/-1%
     Lower bound T4801(normal) peak_megabytes_allocated: 69
     Upper bound T4801(normal) peak_megabytes_allocated: 71
     Actual      T4801(normal) peak_megabytes_allocated: 68
     Deviation   T4801(normal) peak_megabytes_allocated: -2.9 %
 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    T4801(normal) bytes allocated: 464872776 +/-5%
     Lower bound T4801(normal) bytes allocated: 441629137
     Upper bound T4801(normal) bytes allocated: 488116415
     Actual      T4801(normal) bytes allocated: 415645496
     Deviation   T4801(normal) bytes allocated:     -10.6 %
 *** unexpected failure for T4801(normal)
 }}}

 This is on OS X with the master HEAD

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9315#comment:13>
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