[Haskell-cafe] Haskell performance question

Stefan O'Rear stefanor at cox.net
Thu Nov 8 19:24:40 EST 2007


On Thu, Nov 08, 2007 at 07:57:23PM +0100, Thomas Schilling wrote:
> 
> $ ghc --make -O2 ghc-bench.hs
> 
> and got:
> 
> $ time ./ghc-bench 
> 2.0e7
> 
> real    0m0.714s
> user    0m0.576s
> sys     0m0.132s
> 
> $ time ./ghcbC 
> 20000000.000000
> 
> real    0m0.305s
> user    0m0.164s
> sys     0m0.132s
> 
> This is on a first-gen Macbook running Ubuntu.  1GB RAM.  1.83Ghz Core
> Duo
> 
> $ ghc --version
> The Glorious Glasgow Haskell Compilation System, version 6.8.0.20071019
> 
> $ gcc --version
> gcc (GCC) 4.1.2 (Ubuntu 4.1.2-0ubuntu4)
> Copyright (C) 2006 Free Software Foundation, Inc.
> This is free software; see the source for copying conditions.  There is
> NO
> warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR
> PURPOSE.
> 
> 
> _______________________________________________
> Haskell-Cafe mailing list
> Haskell-Cafe at haskell.org
> http://www.haskell.org/mailman/listinfo/haskell-cafe
> $ gcc -O3 ghc-bench.c -o ghcbC
> ghc-bench.c: In function ‘main’:
> ghc-bench.c:16: warning: incompatible implicit declaration of built-in
> function ‘printf’

-O3 is worse than -O0, DO NOT USE IT.

I reported the bug several months ago.  In the meantime, use -O2.

(there are no high optimizations, it's just that the option parser
misparses -O3)

Stefan
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 189 bytes
Desc: Digital signature
Url : http://www.haskell.org/pipermail/haskell-cafe/attachments/20071108/85d694c7/attachment.bin


More information about the Haskell-Cafe mailing list