#9646: Strange performance bug -------------------------------------+------------------------------------- Reporter: erikd | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.8.3 Resolution: | Keywords: Operating System: Linux | Architecture: x86_64 (amd64) Type of failure: Runtime | Difficulty: Unknown performance bug | Blocked By: Test Case: | Related Tickets: Blocking: | Differential Revisions: | -------------------------------------+------------------------------------- Changes (by erikd): * os: Unknown/Multiple => Linux * architecture: Unknown/Multiple => x86_64 (amd64) Comment: @jstolarek : It looks you you do not have the criterion library installed. @dferuer : * Changing the order of the benchmarks makes no difference, the New3* runs still exhibit the same behaviour. * The `make` program is not a factor. I can take the commands printed using `make -n` and put them in a shell script for the same result. * Running the benchmarking program separately from the compile process gives almost identical results. I've also assured myself that the ghc command: {{{ ghc -Wall -Werror -fwarn-tabs -fPIC -ddump-to-file -ddump-prep -ddump-cmm -ddump-opt-cmm -ddump-stg -ddump-asm -O3 -XCPP -XMagicHash -XUnboxedTuples -XUnliftedFFITypes --make bench-integer.hs -o bench-integer }}} is the same in both cases. This is to be expected as `make` really just calls this `ghc --make` command. Behaviour is also the same with `-O2` and `-O1`. I tried compiling with `-O0` which gave radically different results but there were no interesting conclusions to be drawn. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9646#comment:3 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler