[ltp] How much performance improvement going from 32-bit to 64-bit linux?

[Robert Tomsick]

On Thu, 2009-09-17 at 19:43 -0800, portsample wrote:

> Does anyone have any experience with moving from 32-bit linux OS to
> 64-bit? 

Yes, but it was mostly unremarkable.  Instead of installing Debian for
i386 on one machine, I selected amd64 as my target arch.  There wasn't
much more to it.

> What kind of performance increase will I see? 

In theory, more registers means better performance.  In practice, I
suspect you won't notice any difference whatsoever.  I've got several
machines running 32-bit distros and several running 64-bit ones, and
there's no appreciable difference in the performance.

> What kind of problems will I have?

If you've got some old/proprietary software that only works with 32-bit
libs, etc. you might run into problems.  Otherwise you should be set.
Most every open-source package I've seen is 64-bit clean.  With the
distros I've run (Debian and its derivatives, Fedora, and CentOS), there
is no real difference between the 32-bit and the 64-bit versions.

I'd highly recommend Debian or a derivative if you *do* have to deal
with software that expects a 32-bit userland. debootstrap is quite nice.

Best of luck,
-Rob