#13164: idle time full GCs (idle cpu usage) -------------------------------------+------------------------------------- Reporter: lspitzner | Owner: Type: feature request | Status: new Priority: normal | Milestone: Component: Runtime System | Version: 8.0.1 Resolution: | Keywords: idle GC 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 rwbarton): FWIW I've never cared about deadlock detection, and it sounds unreliable in view of lspitzner's most recent comment. I do care that interactive programs I'm not actively using don't consume 12% of my CPU. Doing a GC when the user isn't interacting with the program sounds like a good idea to hide latency. Judging from the detailed GC statistics lspitzner's program isn't totally idle; it must be doing a little bit of work every second, repeatedly triggering a new idle GC. But one would expect it to be cheap to do a little bit of work every second. The heap could be a lot bigger than 50 MB... The user's guide suggests enabling the idle GC for interactive programs, but when there is a little work to do every second it seems basically unusable. And the effects of the idle GC would be lost completely by doing work every 0.2 seconds, which is strange. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13164#comment:5 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler