#6166: Performance regression in mwc-random since 7.0.x -------------------------------------+------------------------------------- Reporter: bos | Owner: Type: bug | Status: new Priority: high | Milestone: 8.0.1 Component: Compiler | Version: 7.4.2 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: x86_64 Type of failure: Runtime | (amd64) performance bug | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by Khudyakov): Does same regression present in latest version of mwc-random? AFAIR performance regression appears because GHC sometimes chose to inline lookup table in where block. It's marked as NOINLINE. It thus was recalculated on each call and caused slowdown. I moved it at top level and problem disapeared. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/6166#comment:18 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler