#14714: RTS Timings on windows are somewhat unreliable -------------------------------------+------------------------------------- Reporter: AndreasK | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.2.2 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- Times given by the RTS are very unreliable on small scales. Part of that is I assume simply the lack of precision. But CPU Time often is reported higher than wall clock time (using the single threaded RTS) as well. Examples: {{{ $ ./binary-trees 12 +RTS -t stretch tree of depth 13 check: -1 ... long lived tree of depth 12 check: -1 <<ghc: 43098232 bytes, 42 GCs, 345148/647488 avg/max bytes residency (2 samples), 3M in use, 0.000 INIT (0.000 elapsed), 0.016 MUT (0.009 elapsed), 0.000 GC (0.003 elapsed) :ghc>> $ ./binary-trees 12 +RTS -t stretch tree of depth 13 check: -1 8192 trees of depth 4 check: -8192 ... 32 trees of depth 12 check: -32 long lived tree of depth 12 check: -1 <<ghc: 43098232 bytes, 42 GCs, 345148/647488 avg/max bytes residency (2 samples), 3M in use, 0.000 INIT (0.000 elapsed), 0.000 MUT (0.010 elapsed), 0.016 GC (0.003 elapsed) :ghc>> }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14714> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler