#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 rwbarton): The "align *_entry to 32 bytes" patch helped tak a lot (~10%), but made no noticeable difference on average over nofib (lots of random changes roughly in the range -3% to 3%). I don't really understand how shifting the address of code by 16 bytes can have such a drastic effect on performance. I guess it must have to do with cache lines, but is using one more cache line really so awful? -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/8279#comment:4 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler