x86-64 on i386 (was Re: Promoting i386 version over x86_64?)

Paul Jakma paul at dishone.st
Mon Dec 14 12:33:26 UTC 2009

On Mon, 14 Dec 2009, Debarshi Ray wrote:

> Regarding shared libraries its worth noting the point about
> "Instruction pointer relative data access":
> http://en.wikipedia.org/wiki/X86-64#Architectural_features

You're missing the point.

If I put you in front of 2 identical machines, one running 32bit and 
one 64bit software, would you be able to tell which one was which, 
from the interactive performance of common applications? I'd be 
willing to bet that for the vast majority of applications you 
wouldn't be.

The point is that few applications need to be 64bit (this may change 
in time, when email and browser apps start to demand 4GB+, but that 
time is a while away - per-process memory demands should stay flat 
for a while if browsers and the like switch from 
single-process/multi-threaded to a multi-processes model).

For the few apps where it makes a difference, sure, run them as 

(Also, please assume in any replies that I have a modicum of clue 
about the low-level technical details between i386 and x86_64).

Paul Jakma	paul at jakma.org	Key ID: 64A2FF6A
magnetic interferance from money/credit cards

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