#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 rrnewton): Would people agree that we should not have spinlocks in the system without some back-off strategy? E.g. switch to sleeping/blocking after some number of iterations. Even a constant upper bound could reign in worst case behaviors. Apparently OS's provide some notion of "adaptive lock" that has other nice features, e.g.: http://stackoverflow.com/questions/19863734/what-is- pthread-mutex-adaptive-np -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9221#comment:62 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler