#14980: Runtime performance regression with binary operations on vectors -------------------------------------+------------------------------------- Reporter: ttylec | Owner: bgamari Type: bug | Status: new Priority: high | Milestone: 8.8.1 Component: Compiler | Version: 8.2.2 Resolution: | Keywords: vector | bitwise operations 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 tdammers): OK, some more experimenting. Changed the .cabal file to force `vector` to `0.12.0.1` (the latest version on hackage); no difference, results are still more or less the same on both compilers. Also managed to get things built with stack; the 8.2 results are also very similar: {{{ "Generated" benchmarking 64 columns/raw unbox vectors time 443.6 μs (443.2 μs .. 443.9 μs) 1.000 R² (1.000 R² .. 1.000 R²) mean 441.6 μs (441.2 μs .. 442.0 μs) std dev 1.364 μs (1.092 μs .. 1.738 μs) benchmarking 64 columns/binary packed time 51.35 μs (51.29 μs .. 51.44 μs) 1.000 R² (1.000 R² .. 1.000 R²) mean 51.07 μs (51.00 μs .. 51.18 μs) std dev 265.9 ns (176.1 ns .. 453.5 ns) benchmarking 256 columns/raw unbox vectors time 446.1 μs (445.5 μs .. 447.2 μs) 1.000 R² (1.000 R² .. 1.000 R²) mean 443.9 μs (443.4 μs .. 444.6 μs) std dev 1.883 μs (1.337 μs .. 3.374 μs) benchmarking 256 columns/binary packed time 291.2 μs (286.2 μs .. 296.9 μs) 0.998 R² (0.998 R² .. 0.999 R²) mean 298.3 μs (294.2 μs .. 301.2 μs) std dev 7.891 μs (5.688 μs .. 10.20 μs) variance introduced by outliers: 15% (moderately inflated) }}} Stack-installed, with 8.0.2: {{{ "Generated" benchmarking 64 columns/raw unbox vectors time 412.3 μs (411.7 μs .. 413.1 μs) 1.000 R² (1.000 R² .. 1.000 R²) mean 412.4 μs (412.0 μs .. 413.1 μs) std dev 1.643 μs (1.124 μs .. 2.815 μs) benchmarking 64 columns/binary packed time 21.89 μs (21.87 μs .. 21.90 μs) 1.000 R² (1.000 R² .. 1.000 R²) mean 21.90 μs (21.89 μs .. 21.91 μs) std dev 38.13 ns (26.94 ns .. 54.15 ns) benchmarking 256 columns/raw unbox vectors time 417.6 μs (416.0 μs .. 419.5 μs) 1.000 R² (1.000 R² .. 1.000 R²) mean 417.2 μs (416.5 μs .. 419.1 μs) std dev 3.403 μs (935.8 ns .. 6.896 μs) benchmarking 256 columns/binary packed time 29.56 μs (29.51 μs .. 29.63 μs) 1.000 R² (1.000 R² .. 1.000 R²) mean 29.52 μs (29.51 μs .. 29.56 μs) std dev 71.00 ns (36.37 ns .. 131.9 ns) }}} So apparently compiling with 8.0.2 through cabal gives different results than compiling though stack. Strange. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/14980#comment:9 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler