[Haskell-cafe] GHC performance of 64-bit

Duncan Coutts duncan.coutts at worc.ox.ac.uk
Sat Jan 6 05:31:08 EST 2007

On Fri, 2007-01-05 at 17:51 +0000, Pedro Baltazar Vasconcelos wrote:
> Hello all,
> I noticed that GHC generates slower code on an Linux amd64 bit platform than the 32-bit version on a cheaper 32-bit machine.
> CPUTime for running sieve of Erathostenes to generate 10,000 primes:
> Athlon XP 2800 (32-bit): 7.98 secs
> Athlon 64 3800 (64-bit): 10.29 secs
> This is using GHC 6.6 on the 64-bit machine and 6.4.1 on the 32-bit one.
> I googled around and could not find any information regarding degraded performance of ghc/haskell on 64-bit machines. Any ideas?

I would suggest re-running that with GHC 6.6. x86-64 support was only
really added in GHC 6.4.1 (in 6.4 it only worked for really simple

However some general info: memory usage is mostly doubled as every
pointer and integer goes from 4 to 8 bytes.


More information about the Haskell-Cafe mailing list