#14193: Add RTS flag to disable 1TB address space allocation -------------------------------------+------------------------------------- Reporter: nh2 | Owner: (none) Type: feature request | Status: patch Priority: normal | Milestone: Component: Compiler | Version: 8.0.2 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: #9706, #14192 | Differential Rev(s): Phab:D3929 Wiki Page: | -------------------------------------+------------------------------------- Comment (by nh2): Replying to [comment:1 simonmar]:
adding a flag to disable the large address space would have a performance cost, because we'd have to check the flag in the inner loop of the GC
@simonmar do you recall if the impact of this was already measured when the new allocator was introduced, or would there be value in me giving it a try? I have some wishful thinking that if branch prediction and pipelining are on our side, we might not be able to measure the additional check -- and if it were so I'd welcome the ability to switch it without recompilation (of ghc, or even better, the program). -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14193#comment:6> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler