[GHC] #9570: cryptarithm1 (normal) has bimodal runtime

[GHC]

#9570: cryptarithm1 (normal) has bimodal runtime
-------------------------------------+-------------------------------------
       Reporter:  ezyang             |                   Owner:
           Type:  bug                |                  Status:  new
       Priority:  normal             |               Milestone:
      Component:  NoFib benchmark    |                 Version:  7.9
  suite                              |        Operating System:
       Keywords:                     |  Unknown/Multiple
   Architecture:  Unknown/Multiple   |         Type of failure:
     Difficulty:  Unknown            |  None/Unknown
     Blocked By:                     |               Test Case:
Related Tickets:                     |                Blocking:
                                     |  Differential Revisions:
-------------------------------------+-------------------------------------
 I was investigating performance numbers for cryptarithm1 in #8199, I
 noticed that the numbers for this benchmark were curiously bimodal. Here
 are two representative samples from both sides of the distribution.

 {{{
 ../../runstdtest/runstdtest ./cryptarithm1  -o1 cryptarithm1.stdout -o1
 cryptarithm1.stdout  -ghc-timing     ;   ../../runstdtest/runstdtest
 ./cryptarithm1  -o1 cryptarithm1.stdout -o1 cryptarithm1.stdout  -ghc-
 timing     ;   ../../runstdtest/runstdtest ./cryptarithm1  -o1
 cryptarithm1.stdout -o1 cryptarithm1.stdout  -ghc-timing     ;
 ../../runstdtest/runstdtest ./cryptarithm1  -o1 cryptarithm1.stdout -o1
 cryptarithm1.stdout  -ghc-timing     ;   ../../runstdtest/runstdtest
 ./cryptarithm1  -o1 cryptarithm1.stdout -o1 cryptarithm1.stdout  -ghc-
 timing     ;

 real    0m0.676s
 user    0m0.660s
 sys     0m0.013s
 <<ghc: 2051819320 bytes, 3929 GCs (3927 + 2), 0/0 avg/max bytes residency
 (0 samples), 5221368 bytes GC work, 1M in use, 0.000 INIT (0.000 elapsed),
 0.643 MUT (0.643 elapsed), 0.026 GC (0.026 elapsed), 0.026 GC(0) (0.025
 elapsed), 0.000 GC(1) (0.000 elapsed), 1 balance :ghc>>

 real    0m0.610s
 user    0m0.603s
 sys     0m0.007s
 <<ghc: 2051819320 bytes, 3929 GCs (3927 + 2), 0/0 avg/max bytes residency
 (0 samples), 5221368 bytes GC work, 1M in use, 0.000 INIT (0.000 elapsed),
 0.582 MUT (0.582 elapsed), 0.023 GC (0.023 elapsed), 0.023 GC(0) (0.023
 elapsed), 0.000 GC(1) (0.000 elapsed), 1 balance :ghc>>
 }}}

 I don't have any further resolution on the problem yet.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9570>
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