[GHC] #16224: CPUTime001 is fragile

[GHC]

#16224: CPUTime001 is fragile
-------------------------------------+-------------------------------------
        Reporter:  bgamari           |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.6.3
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
-------------------------------------+-------------------------------------
Description changed by bgamari:

Old description:

> I have seen CPUTime001 fail spuriously on several occasions. In
> [[https://gitlab.haskell.org/ghc/ghc/-/jobs/15989|one such occasion]]:
> {{{#!diff
> --- libraries/base/tests/CPUTime001.run/CPUTime001.stdout.normalised
> 2019-01-23 18:53:32.601027719 +0000
> +++ libraries/base/tests/CPUTime001.run/CPUTime001.run.stdout.normalised
> 2019-01-23 18:53:32.601027719 +0000
> @@ -1,4 +1,4 @@
>  1028457
>  1664079
>  2692537
> -(True,True)
> +(False,True)
> }}}

New description:

 I have seen CPUTime001 fail spuriously on several occasions. In
 [[https://gitlab.haskell.org/ghc/ghc/-/jobs/15989|one such occasion]] on
 Debian 9 the `normal` testsuite way failed with:
 {{{#!diff
 --- libraries/base/tests/CPUTime001.run/CPUTime001.stdout.normalised
 2019-01-23 18:53:32.601027719 +0000
 +++ libraries/base/tests/CPUTime001.run/CPUTime001.run.stdout.normalised
 2019-01-23 18:53:32.601027719 +0000
 @@ -1,4 +1,4 @@
  1028457
  1664079
  2692537
 -(True,True)
 +(False,True)
 }}}

--

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/16224#comment:1>
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