
#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 ezyang): I was chatting with one of my colleagues about this problem recently, and they said something very provocative: if GHC is not scaling because there is some global mutable state (e.g. the NameCache) which all the threads are hitting, it doesn't make sense to try to fix the compiler to scale; you should just run multiple processes of the compiler in parallel (like GHC's build does). Guaranteed scaling! Do people agree with this viewpoint? Disagree? If we take this viewpoint seriously, we should spend more time improving GHC's ability to output the dependency analysis for other tools to then build. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9221#comment:23 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler