#11054: GHC on Windows could not use more than 64 logical processors -------------------------------------+------------------------------------- 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: -------------------------------------+------------------------------------- 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_proce... MSDN link https://msdn.microsoft.com/en- us/library/windows/desktop/dd405503(v=vs.85).aspx -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/11054 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler