#16034: Quadratic GC slowdown using RTS debug -------------------------------------+------------------------------------- Reporter: remyo | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Runtime System | Version: 8.6.3 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 osa1): I don't think this is a bug. As you already found out we do `countBlock()` a lot in debug runtime for sanity checking (`perf` shows that your example spends 72% of the time in `countBlocks()`), which traverses linked lists of blocks. This takes more time as residency increases. Out of curiosity, why do you want debug runtime to be faster? Debug runtime is supposed to make debugging easier, and for that we do lots of sanity checking. It'd be strange to optimise debug runtime for runtime performance instead of ease of debugging. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/16034#comment:2 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler