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

Gregory Maxwell gmaxwell at gmail.com
Mon Dec 14 16:12:37 UTC 2009

On Mon, Dec 14, 2009 at 7:33 AM, Paul Jakma <paul at dishone.st> wrote:
> 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.

Yet I could tell from the applications where performance is important.
You reject my metric, I reject yours. Something of an impasse.

> time, when email and browser apps start to demand 4GB+, but that time is a
> while away

I enjoyed how in nearly one breath you claim that performance is usually
irrelevant then go on to name an application where performance is quite
visible: A considerable amount of page load time is browser rendering.

(It's also not too hard to make firefox use more than 3GB of virtual
address space, though I admit you do need to work at it a little)

What was the point of this conversation again?

People have demonstrated on this list, with benchmarks, that x86_64 makes a
material performance improvement across a broad swath of applications where
performance matters.

You point out that users don't care about performance in many cases. I do not
disagree but I have no clue how we can qualify or quantify that.

Certainly, when some website posts benchmarks of Fedora vs other distribution
those threads get a lot of discussion but that isn't really evidence.

I also do not know how it is relevant, in context of x86_64, to Fedora as the
use of x86_64 is effectively free. The costs, such as reduced compatibility
with binary browser plugins, are simply not relevant to many people.

You're obviously convinced of your opinion, other people hold the view that
good performance is part of the distribution's core job.

Other than the point that x86_64 also increases security (from greatly
increased address space layout randomization, and reduced PIE cost), I think
we've hit on every point for and against using x86_64 in this thread— yet
I think not a single person has changed their initial view.

I don't see how any resolution is going to come from further discussion.

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