#9221: (super!) linear slowdown of parallel builds on 40 core machine -------------------------------------+------------------------------------- Reporter: carter | Owner: Type: bug | Status: new Priority: normal | Milestone: 8.2.1 Component: Compiler | Version: 7.8.2 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: Compile-time | Unknown/Multiple performance bug | Test Case: Blocked By: | Blocking: Related Tickets: #910, #8224 | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by simonmar): So I think this tells us that it is not memory bandwidth saturation, right? Because running individual GHC processes scales better than a single parallel GHC. To be sure, you should also use the larger heap settings with the `make -jN` runs. So there is still extra contention in `ghc -jN`. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9221#comment:67 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler