#15998: GHC.Event.Thread.eventManager has a lot of indirections -------------------------------------+------------------------------------- Reporter: chessai | Owner: (none) Type: feature | Status: new request | Priority: normal | Milestone: 8.6.3 Component: | Version: 8.6.2 libraries/base | 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: -------------------------------------+------------------------------------- Current `eventManager`: {{{#!hs eventManager :: IORef (IOArray Int (Maybe (ThreadId, EventManager))) eventManager = unsafePerformIO $ do ... }}} That's a lot of indirections just to grab your thread's event manager. Consider the following, which I believe would improve the performance of this: {{{#!hs data UnliftedIORef :: TYPE 'UnliftedRep -> Type where UnliftedIORef :: MutVar# RealWorld a -> UnliftedIORef a eventManager :: UnliftedIORef (MutableArray# RealWorld Things) data Things = Things !ThreadId !EventManager }}} I think the Maybe can be eliminated. I'm unsure. What makes me think it can be is the following snippet: {{{#!hs getSystemEventManager :: IO (Maybe EventManager) getSystemEventManager = do t <- myThreadId (cap, _) <- threadCapability t eventManagerArray <- readIORef eventManager mmgr <- readIOArray eventManagerArray cap return $ fmap snd mmgr getSystemEventManager_ :: IO EventManager getSystemEventManager_ = do Just mgr <- getSystemEventManager return mgr {-# INLINE getSystemEventManager_ #-} }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/15998 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler