Re: should I go for 64bit version of Fedora 11 ?

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Once upon a time, Cameron Simpson <cs@xxxxxxxxxx> said:
> On 03Nov2009 23:45, Alan Cox <alan@xxxxxxxxxxxxxxxxxxx> wrote:
> | Such as the kernel ... which is much happier in 64bit mode with over 1GB
> | of RAM.
> 
> Is there some URL I could visit that qualifies this?
> 
> I'm not doubting you, but I would like to have a mental model of roughly
> why and how 64-bit mode benefits a system.

If you have 1G (or really a little less) of physical RAM on 32-bit x86,
the kernel can map all of it into the kernel's virtual address space.
Otherwise, it has to use different addressing to access physical
addresses, IIRC mapping them on demand (which adds overhead).

On a 64-bit system, all of physical memory can be mapped into the kernel
address space at all times.

Also, x86_64 has a larger CPU register set, which can speed up some
operations.

-- 
Chris Adams <cmadams@xxxxxxxxxx>
Systems and Network Administrator - HiWAAY Internet Services
I don't speak for anybody but myself - that's enough trouble.

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