#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): Another data point: I dumped stack's `cabal.config` for the LTS 11.1 release into my cabal project and compiled with `--with- compiler=/usr/local/bin/ghc-8.2.2`, and the result I'm getting is this: {{{ "Generated" benchmarking 64 columns/raw unbox vectors time 460.0 μs (447.0 μs .. 473.6 μs) 0.995 R² (0.992 R² .. 0.997 R²) mean 446.4 μs (440.2 μs .. 455.1 μs) std dev 24.42 μs (17.29 μs .. 31.22 μs) variance introduced by outliers: 48% (moderately inflated) benchmarking 64 columns/binary packed time 52.25 μs (51.66 μs .. 53.04 μs) 0.998 R² (0.997 R² .. 0.999 R²) mean 52.60 μs (51.99 μs .. 53.67 μs) std dev 2.665 μs (1.919 μs .. 4.073 μs) variance introduced by outliers: 55% (severely inflated) benchmarking 256 columns/raw unbox vectors time 439.9 μs (434.4 μs .. 447.4 μs) 0.998 R² (0.997 R² .. 1.000 R²) mean 439.0 μs (435.0 μs .. 446.4 μs) std dev 17.95 μs (10.79 μs .. 27.38 μs) variance introduced by outliers: 35% (moderately inflated) benchmarking 256 columns/binary packed time 304.7 μs (288.7 μs .. 330.4 μs) 0.965 R² (0.940 R² .. 0.998 R²) mean 324.1 μs (302.9 μs .. 364.4 μs) std dev 62.33 μs (26.19 μs .. 97.61 μs) variance introduced by outliers: 91% (severely inflated) }}} However, I'm getting the same bad behavior when I pin libraries to LTS 11.15, and also when I don't pin libraries at all. So it's not the libraries. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/14980#comment:20 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler