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Subject: Re: [OMPI users] Issues on install 1.3.1
From: Francesco Pietra (chiendarret_at_[hidden])
Date: 2009-04-03 05:11:20


As far as I understand,

apt-get install libnuma1 libnuma-dbg libnuma-dev

installs libnuma libraries 64 bit in /usr/lib there also two symlinks
/usr/lib32 and /usr/lib64 but there is no trace of the libnuma
libraries there.

That the computational codes I use run twice as fast at 64 bit than 32 bit

thanks
francescois well established.

On Fri, Apr 3, 2009 at 3:14 AM, Iain Bason <Iain.Bason_at_[hidden]> wrote:
>
> On Apr 2, 2009, at 2:45 PM, Gus Correa wrote:
>
>> Sorry, I don't have an answer about performance.
>> You may need to ask somebody else or google around
>> about the relative performance of 32-bit vs. 64-bit mode.
>
> It is worth trying 64-bit.  The performance is going to depend on the
> program.  Since 64 bit pointers take more cache space, a program that uses a
> lot of pointers will run more slowly.  However, the x64 architecture has
> more registers than the x86 architecture, and that can make a 64 bit program
> run faster.  Overall, it is probably more common for program to run faster
> in 64 bit mode, but your program could be in the minority.
>
> Iain
>
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