mjs at CLEMSON.EDU
Mon Oct 22 19:56:38 UTC 2007
On Mon, 2007-10-22 at 12:20 -0400, Jesse Keating wrote:
> On Mon, 22 Oct 2007 12:03:05 -0400
> Matthew Saltzman <mjs at CLEMSON.EDU> wrote:
> > 32-bit runtime in general? Why? (Not a critical "why", a genuinely
> > curious "why"...)
> On those arches, running 64bit code comes at a penalty. In fact, even
> on x86_64 there is a penalty. Larger memory overhead. However on
> x86_64 the extra CPU registers gained by running in x86_64 mode
> outweigh the memory overhead. Not the case on ppc/sparc where there
> are no 'extra registers' to gain. Very little software in very few
> situations need 64bit.
So on those archs one would want a 64-bit kernel and 32-bit apps, except
for large-memory programs or those needing 64/128-bit numerical types
(self-developed code, for example)?
Is that how it's actually handled by the installer?
Clemson University Math Sciences
mjs AT clemson DOT edu
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