#14981: GHC parallel GC is not doing well on modern many-core machine -------------------------------------+------------------------------------- Reporter: varosi | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Runtime System | Version: 8.4.1 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by bgamari): Minor GCs indeed do necessarily stop-the-world. This is a known limitation which affects large core-counts particularly badly. However, fixing this in a copying garbage collector is quite tricky. There have been a few attempts at avoiding this stop-the-world. The most recent attempt is the Simons' "Multicore Garbage Collection with Local Heaps". You can still find the prototype implementation (against GHC 6.10, IIRC) on the `wip/local-heaps` branch but it not merged as the performance improvement of brought by this change was outweighed by its enormous complexity. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/14981#comment:6 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler