#12964: Runtime regression to RTS change -------------------------------------+------------------------------------- Reporter: nomeata | Owner: Type: bug | Status: new Priority: highest | Milestone: 8.2.1 Component: Runtime | Version: 8.1 System | 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 commit to fix #12799, namely changeset:1732d7ac43ca, seems to have introduced a runtime regression. The hidden and integer nofib benchmarks regress by 5.5% resp. 2.5%: https://perf.haskell.org/ghc/#revision/1732d7ac43ca578deca39ea5a63cbf34f3cd9... I re-measured this commit and its parent once, and the numbers aid not change much. The `hidden` regression seems to be offset almost completely by the later changeset:6f7ed1e51bf360621a3c2a447045ab3012f68575 while the `integer` regression got “fixed” by the later changeset:1732d7ac43ca578deca39ea5a63cbf34f3cd9dd5. The perf builder is still new, so this might be bogus. But we should still check. Also, maybe random changes to the RTS cause random changes to the code layout which surface here. Or there is a real cause. Simon Marlow [https://phabricator.haskell.org/rGHC1732d7ac43ca#56419 suggested] to open a high priority ticket for this. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/12964 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler