#12181: Multi-threaded code on ARM64 GHC runtime doesn't use all available cores --------------------------------------------+------------------------------ Reporter: varosi | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Runtime System | Version: 7.10.3 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: arm Type of failure: Runtime performance bug | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | --------------------------------------------+------------------------------ Comment (by varosi): The problem seems to be more deep. Currently we run a program written in C for profiling of matrix multiplication and it runs on all cores. When we run Haskell program with "+RTS -N8" (fix for number of cores) it runs 8 OS threads but they are taking just half of available cores and program runs much slower than running it with "+RTS -N4". This is the program for reference: https://bitbucket.org/varosi/cgraytrace/overview -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/12181#comment:3 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler