[GHC] #11054: GHC on Windows could not use more than 64 logical processors

[GHC]

#11054: GHC on Windows could not use more than 64 logical processors
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           Reporter:  varosi         |             Owner:
               Type:  bug            |            Status:  new
           Priority:  normal         |         Milestone:
          Component:  Runtime        |           Version:  7.10.2
  System                             |
           Keywords:                 |  Operating System:  Windows
       Architecture:  x86_64         |   Type of failure:  Runtime
  (amd64)                            |  performance bug
          Test Case:                 |        Blocked By:
           Blocking:                 |   Related Tickets:
Differential Rev(s):                 |         Wiki Page:
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 I found that GHC runtime does not take advantage of processor groups under
 Windows. So it cannot use more than 64 logical processors (2x 18 core
 physical + HT).

 This is Reddit thread about:
 https://www.reddit.com/r/haskell/comments/3q1r0o/ghc_on_numa_72_core_2_processor_machine_cannot/

 MSDN link
 https://msdn.microsoft.com/en-
 us/library/windows/desktop/dd405503(v=vs.85).aspx

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11054>
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