32-bit vs. 64-bit x86 Speed

Jon Forrest <jlforrest@berkeley.edu>
11 Apr 2007 23:33:44 -0400

          From comp.compilers

Related articles
32-bit vs. 64-bit x86 Speed jlforrest@berkeley.edu (Jon Forrest) (2007-04-11)
Re: 32-bit vs. 64-bit x86 Speed gah@ugcs.caltech.edu (glen herrmannsfeldt) (2007-04-13)
Re: 32-bit vs. 64-bit x86 Speed marcov@stack.nl (Marco van de Voort) (2007-04-13)
Re: 32-bit vs. 64-bit x86 Speed anton@mips.complang.tuwien.ac.at (2007-04-13)
Re: 32-bit vs. 64-bit x86 Speed DrDiettrich1@aol.com (Hans-Peter Diettrich) (2007-04-13)
Re: 32-bit vs. 64-bit x86 Speed ian.rogers@manchester.ac.uk (Ian Rogers) (2007-04-13)
Re: 32-bit vs. 64-bit x86 Speed meissner@the-meissners.org (Michael Meissner) (2007-04-13)
[13 later articles]
| List of all articles for this month |

From: Jon Forrest <jlforrest@berkeley.edu>
Newsgroups: comp.compilers
Date: 11 Apr 2007 23:33:44 -0400
Organization: University of California, Berkeley
Keywords: code, performance, question
Posted-Date: 11 Apr 2007 23:33:44 EDT

I recently made a claim on the Beowulf email list that somebody
questioned me on. After some reflection, I'm not as sure as I once was
that I'm correct. I'm wondering what you compiler people have to say
about this.

Here's what I said:

"One thing I've noticed about 64-bit computing in general is that it's
being oversold. The **only** reason for running in 64-bit mode is if
you need the additional address space. Indeed, for some apps this is
critical and 64-bit computing solves a real problem. For apps that
don't need the extra address space, the benefits of the additional
registers in x86-64 are nearly undone by the need to move more bits
around, so 32-bit and 64-bit modes are pretty much a push. When you
add the additional difficulty of getting 64-bit drivers and what-not,
I don't think it's worth messing with 64-bit computing for apps that
don't need the address space."

Let's say you're a Linux user who never needs to run programs that
don't fit in 32-bits. Would you run a 32-bit or a 64-bit version of
Linux? You compiler people probably have intimate knowledge of the ISA
issues here so I'm interested in what you have to say.

Jon Forrest
Unix Computing Support
College of Chemistry
173 Tan Hall
University of California Berkeley
Berkeley, CA

Post a followup to this message

Return to the comp.compilers page.
Search the comp.compilers archives again.