[GHC] #14714: RTS Timings on windows are somewhat unreliable

[GHC]

#14714: RTS Timings on windows are somewhat unreliable
-------------------------------------+-------------------------------------
        Reporter:  AndreasK          |                Owner:  (none)
            Type:  bug               |               Status:  closed
        Priority:  low               |            Milestone:
       Component:  Runtime System    |              Version:  8.2.2
      Resolution:  wontfix           |             Keywords:
Operating System:  Windows           |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
-------------------------------------+-------------------------------------
Changes (by AndreasK):

 * status:  new => closed
 * component:  Compiler => Runtime System
 * resolution:   => wontfix
 * os:  Unknown/Multiple => Windows
 * priority:  normal => low


Comment:

 There seems to be no way around this.

 The windows cpuTime information comes from `GetProcessTimes` while the
 elapsed time uses `QueryPerformanceCounter`.

 GetProcessTimes has a lower accuracy which leads to these result for
 cpuTime.

 QueryProcessCycleTime would have better resolution but measures cycles not
 time. This works fine for benchmarking where one would disable frequency
 scaling anyway.
 But It would lead to confusing results otherwise.

 Marking this as wontfix for now as I don't think there is a better
 solution available currently.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14714#comment:1>
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