#8224: Excessive system time -- new IO manager problem? -------------------------------------+------------------------------------- Reporter: rrnewton | Owner: Type: bug | Status: new Priority: high | Milestone: 7.8.1 Component: Runtime System | Version: 7.7 Resolution: | Keywords: IO Manager, Operating System: Linux | System Time Type of failure: Runtime | Architecture: x86_64 (amd64) performance bug | Difficulty: Unknown Test Case: | Blocked By: Blocking: | Related Tickets: -------------------------------------+------------------------------------- Comment (by simonmar): The first safe call on each Capability will cause the creation of a new OS thread, which probably accounts for some of the cost. From the strace profile it looks like there is some contention too. It might be useful to do some mutex profiling to see what lock is being contended for - perhaps it is `all_tasks_mutex`. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/8224#comment:15 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler