#11116: GC reports memory in use way below the actual -------------------------------------+------------------------------------- Reporter: | Owner: facundo.dominguez | Type: bug | Status: closed Priority: normal | Milestone: Component: Runtime System | Version: 7.10.2 Resolution: invalid | Keywords: Operating System: Linux | Architecture: x86_64 Type of failure: Runtime | (amd64) performance bug | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Changes (by rwbarton): * status: new => closed * resolution: => invalid Comment: `currentBytesUsed` and `maxBytesUsed` are, as documented, "Current number of live bytes" on the heap and "Maximum number of live bytes seen so far" respectively. They are just calculated as the sum of the sizes of all live objects on the heap. Due to the way GHC's copying garbage collector works, the actual space used by the heap will typically be double this size. Then of course there will be additional space used by the runtime system or other C libraries (though that is not significant in this example). `peakMegabytesAllocated` counts everything allocated through the RTS (including any blocks used for heap) and will be closer to the figure you are looking for. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/11116#comment:2 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler