#14208: Performance with O0 is much better than the default or with -O2, runghc performs the best -------------------------------------+------------------------------------- Reporter: harendra | Owner: osa1 Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.2.1 Resolution: | 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: | -------------------------------------+------------------------------------- Comment (by mpickering): I cloned the repo - https://github.com/composewell/streamly/tree/199e20dd4b62ac2dafea0a40dc2ce3d... Checked out commit - 199e20dd4b62ac2dafea0a40dc2ce3d97c307542 I could build all the dependencies with ghc-8.2.2. Then I ran in in the root of the repo {{{ ghc benchmarks/Main.hs -isrc/ -O2 }}} and then ran the executable. The benchmark numbers were slower than doing the same without `-O2`. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/14208#comment:39 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler