#15620: Speed up Data.Unique -------------------------------------+------------------------------------- Reporter: dfeuer | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: 8.6.1 Component: Core | Version: 8.4.3 Libraries | Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: Runtime Unknown/Multiple | performance bug Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- The current `Data.Unique` code seems heavier than necessary: 1. It uses `Integer` when it can surely get away with less than two words on 64-bit systems. 2. It effectively guarantees that uniques will be consecutive, which isn't very useful. I don't know how to fix this, but I'm confident there's a better way out there. One silly idea: use one 100 or so-bit counter per capability. Use the rest of the bits to distinguish among the capabilities. To reduce hash collisions, make each capability increment its counter by a different prime number (or something like that). -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/15620 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler