Re: AMD response about Debian x86-64 port

[Arnd Bergmann <arnd@bergmann-dalldorf.de>]

On Friday 10 January 2003 21:49, Bart Trojanowski wrote:
> * Steve Greenland <steveg@moregruel.net> [030110 15:01]:
> > Now, simplicity and package porter sanity may just say "compile
> > 64-bit unless there is a functional reason not to", but 64bit->better
> > performance is not a forgone conclusion.
>
> I agree.  64bit is not an improvement for _all_ applications.  However,
> please remember that the "64-bit" mode of x86-64 not only doubles the
> width of registers, but also doubles the number of them.  While being
> bigger and hence increasing load time, switching software to this mode
> (from 32bit compatibility mode) will benefit from this greatly in some
> cases.

Moreover, mixing 32 bit and 64 bit applications is usually a bad idea,
because it means you could have to map all shared libraries twice. In the 
worst case, you can waste tens of MBs of RAM and 50% of your instruction
cache.

	Arnd <><