64-bit vs 32-bit userspace/kernel benchmark? Was: Athlon 64 X2 cpuinfooddities

From: Jeffrey Hundstad
Date: Tue Jan 10 2006 - 15:21:49 EST


Jesper Juhl wrote:

On 1/10/06, Andi Kleen <ak@xxxxxxx> wrote:


On Tuesday 10 January 2006 03:12, Jesper Juhl wrote:


...

Ah - how legacy.



Yeah, but since my distro of choice is 32bit only and I don't much
feel like porting it myself or using an unofficial port (slamd64) I'm
sticking with a 32bit userspace. And as long as userspace is pure
32bit there doesn't seem to be much point in building a 64bit kernel.
And I only have 2GB of RAM, so I don't have a use for the larger 64bit
address space.
I also don't run any apps that do a lot of math on >32bit numbers, so
there's not much gain there either.
I guess I would bennefit from the extra GPR's, but then I would at the
same time loose a bit by all pointers being 64bit - both lose some
disk space due to larger binaries and I'd have increased memory use
and less efficient L1/L2 cache use.

I don't think there would actually be much gain for me in switching to
a 64bit kernel with a 64bit userspace atm.
But if I'm wrong I'd of course love to hear about it :)




Has anyone done any actual benchmark tests that show 64-bit vs 32-bit environments/distributions with Athlon64 processors. If so, I love to see the results. I too elected to stick with 32-bit, using the same reasoning/guessing above.

--
Jeffrey Hundstad

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