#8732: Global big object heap allocator lock causes contention -------------------------------------+------------------------------------ Reporter: tibbe | Owner: simonmar Type: bug | Status: new Priority: normal | Milestone: Component: Runtime System | Version: 7.6.3 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Unknown/Multiple Type of failure: None/Unknown | Difficulty: Unknown Test Case: | Blocked By: Blocking: | Related Tickets: -------------------------------------+------------------------------------ Description changed by tibbe: Old description:
The lock allocate() takes when allocating big objects hurts scalability of I/O bound application. Network.Socket.ByteString.recv is typically called with a buffer size of 4096, which causes a ByteString of that size to be allocate. The size of this ByteString causes it to be allocated from the big object space, which causes contention of the global lock that guards that space.
See http://www.yesodweb.com/blog/2014/02/new-warp for a real world example.
New description: The lock `allocate` takes when allocating big objects hurts scalability of I/O bound application. `Network.Socket.ByteString.recv` is typically called with a buffer size of 4096, which causes a `ByteString` of that size to be allocated. The size of this `ByteString` causes it to be allocated from the big object space, which causes contention of the global lock that guards that space. See http://www.yesodweb.com/blog/2014/02/new-warp for a real world example. -- -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/8732#comment:1 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler