#8279: bad alignment in code gen yields substantial perf issue --------------------------------------------+------------------------------ Reporter: carter | Owner: Type: bug | Status: new Priority: highest | Milestone: Component: Compiler | Version: 7.7 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: Runtime performance bug | Unknown/Multiple Test Case: | Difficulty: Unknown Blocking: | Blocked By: | Related Tickets: --------------------------------------------+------------------------------ Comment (by simonmar): I've noticed things like this in the past. One hypothesis is that when the code is tightly packed together the branch predictor doesn't work so well, but that's just a guess. The way forward is to do systematic measurements with all of nofib, measuring performance counters and code size with various alignment strategies. Also someone could thoroughly read the latest Intel optimization guides and see if we're doing the right things. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/8279#comment:6 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler