Re: [Caml-list] 32- and 64-bit performance

[Alex Baretta <alex@barettadeit.com>]

Jon Harrop wrote:
> I just bought a new Athlon 64 laptop and installed 32- and 64-bit Debian.
> Here are some timings, showing the performance change when moving from 32-
> to 64-bit using ocamlopt (3.08.2) and g++ (3.4.4):
...
> 
> So ocamlopt does seem to generate significantly better code in these examples, 
> particularly when they are floating point intensive. Also, only one test is 
> slower in 64-bit, due to its heavy use of trees.
> 

Why do you suppose is there *any* benchmark faster in 32 bit mode than 
in 64 bit mode on the Athlon64? Since the AMD64 architecture is 
generally better than IA32--were it only for the additional registers--I 
would expect all benchmarks to run as fast or faster when compiled to 
the AMD64 instruction set.

Alex

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