#9221: (super!) linear slowdown of parallel builds on 40 core machine -------------------------------------+------------------------------------- Reporter: carter | Owner: Type: bug | Status: new Priority: high | Milestone: 7.12.1 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 | Differential Revisions: -------------------------------------+------------------------------------- Comment (by simonmar): It sounds like there might be a lot of threads hitting blackholes, with consequent context-switching churn. Finding out which blackhole would be good - probably something in a shared data structure (NameCache or the FastString table, perhaps). ThreadScope would be a good next step. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9221#comment:31 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler