[ubuntu-us-ut] 64-bit vs 32-bit (Was: Re: 10.04 CD shipment ordered)

[Christer Edwards]

On Wed, Apr 7, 2010 at 3:26 PM, Aaron Toponce <aaron.toponce at gmail.com> wrote:
...[snip]...
> Continuing on with RAM, no matter how much you have installed, or if you
> have PAE on your CPU, no process can address more than 3GB on a 3:1
> split, 4GB max, if you're doing 4:4. So, if you have 3GB or more RAM in
> your system, the only way to fully utilize it for any application on the
> system is to go 64-bit.

Right. Like I said, if you have more than 4G you *need* 64bit. It
would be a waste of memory, even with PAE, to have 4G+ and not use
64bit.

> Going even further with RAM, 64-bit kernel can physically support,
> currently, 1TB RAM sticks, which the ability to be extended to 4PB of
> RAM sticks.

Not really applicable I think. If you've got 1TB of ram, again, you're
going to run 64bit (you *have* to). I know what 64bit *can* do, but
1TB-4PB goes beyond my argument. You have 4G+, therefore use 64bit.
And even if we're talking about addressable, or virtual memory.
Between my RAM and HDD I don't have near that much, and what the hell
am I running that is going to use 1TB+ or memory? Holy crap!

...[snip]...
> Now, the drawbacks. It's not all peaches and cream. The biggest drawback
> to 64-bit, is the lack of a 64-bit flash browser plugin from Adobe. For
> the desktop, that is. Right there, that hinders 64-bit adoption on the
> desktop rather quickly, which may be a big reason why Canonical isn't
> bothering to ship 64-bit pressed CDs, and why Microsoft isn't really
> pushing their 64-bit Windows operating systems either.

I believe this is reliable enough now, at least on Linux, with a
wrapper, but you're right. Adobe isn't helping anybody by not
providing 64bit builds (but Flash is evil anyway, so what do we care
:P)

> Another problem is the increased size of a 64-bit binary versus a 32-bit
> one. On top of the larger binary, 64-bit processes typically have higher
> memory consumptions due to larger data structures. My experience has
> shown that the range for additional memory consumption is around 2-5%,
> compared to 32-bit.

This is my issue with it right here. I don't have 4G+ so I don't
*need* it, and it will it turn use *more* drive space and memory than
the equivalent installation on 32bit. I don't get many of the benefits
(yes, some of the technical benefits still apply, but I don't think
they are noticeable to the end-user), but I do get the drawbacks.

I have a 256M Linode that I installed Debian stable 64bit on. I am
planning on reinstalling it on 32bit because, and particularly in this
case, I am limited on the amount of RAM that I have and 64bit uses
*more* than the same 32bit installation. In a situation where I'm
paying per-RAM, using more is not what I want. When monitoring my
server it sure feels like the 64bit installation is *less* efficient
than the 32bit equivalent.

> However, due to the x86_64 architecture, you have the capability to run
> 32-bit applications on a 64-bit operating system. Which means, if there
> is some "critical" application (like flash) that isn't compiled for a
> 64-bit arch, no big deal. Grab the 32-bit version, and execute away.
>
> So, really, there's no reason to NOT run a 64-bit operating system on
> 64-bit hardware. The performance and reliability benefits far outweigh
> the few drawbacks that I've mentioned above. In the GNU/Linux world, I
> would say with confidence that 99% of upstream applications with source
> available have been compiled for 64-bit as well as 32-bit. I've been
> running 64-bit exclusively now, for almost 3 years, and I have yet to
> run into an application where source was available that is not compiled
> for the 64-bit architecture.
...[snip]...

...except for flash, opera, adobe reader--quite a few non-free
applications that are still very popular.

> Conclusion: it's just silly to say "unless you have 4+ GB RAM, there is
> no reason to run 64-bit". If you have the hardware, you should take
> advantage of it.

Again, while you've presented a lot of "technical" benefits, as and
end-user I'm still not sold on it. All of the theoretical hella-bytes
of RAM that it *could* use don't matter. I have 2G. That's all it can
or will use. It might be able to push more through the bus, but in
doing so it's going to use more of the (limited) 2G that I have in
order to do so. If one is a benefit and the other is a negative, we're
cancelled out at that point. And the final thing is that there are
still quite a few popular (albeit non-free) applications that are
32bit only. I can try to wrap them in ia32-libs (or whatever the
package is called), or I can just not worry about it and know that
*everything* is available on 32bit.

If you have 4G+, absolutely use 64bit. You'd be crazy and wasteful not to.

If you don't, well.. it's up to you, but I still won't bother.

I still think you're running it mostly on principle (if you're going
to pick on me a little, I'm going to do the same) ;)

-- 
Christer Edwards