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32- and 64-bit performance
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Date: -- (:)
From: Alexander S. Usov <A.S.Usov@K...>
Subject: Re: [Caml-list] 32- and 64-bit performance
On Wednesday 30 March 2005 09:46, Alex Baretta wrote:
> Jon Harrop wrote:
> > 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.

A one of the simplest reasons -- somewhat increased memory use.
And memory access is incredibly expensive novadays.

-- 
Best regards,
  Alexander.