Re: [GHC] #7923: Optimization for takeMVar/putMVar when MVar left empty

#7923: Optimization for takeMVar/putMVar when MVar left empty ---------------------------------+------------------------------------------ Reporter: ezyang | Owner: ezyang Type: task | Status: patch Priority: normal | Milestone: Component: Runtime System | Version: 7.7 Keywords: | Os: Unknown/Multiple Architecture: Unknown/Multiple | Failure: Runtime performance bug Difficulty: Unknown | Testcase: Blockedby: | Blocking: Related: | ---------------------------------+------------------------------------------ Comment(by ian@…): commit 5d9e686c30a00be08a04d9fd1c860994153a1f7a {{{ Author: Ian Lynagh Date: Sat Jun 15 13:19:21 2013 +0100 Optimization for takeMVar/putMVar when MVar left empty; fixes #7923 We only need to apply the write barrier to an MVar when it acquires a reference to live data; when the MVar is left empty in the case of a takeMVar/putMVar, we can save a memory reference. Patch from Edward Z. Yang. rts/PrimOps.cmm | 49 +++++++++++++++++++++++++++++-------------------- 1 files changed, 29 insertions(+), 20 deletions(-) }}} -- Ticket URL: http://hackage.haskell.org/trac/ghc/ticket/7923#comment:4 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler