Re: Intel C2D COREs not used equally in FreeBSD 7.0-CURRENT i386

On Wed, 6 Jun 2007, Doug Ambrisko wrote:

> Dag-Erling Sm\xc3\xb8rgrav writes:
> | Oliver Fromme <olli_at_lurza.secnetix.de> writes:
> | > It's a common mistake to assume that amd64 only makes sense
> | > if you have >= 4GB RAM.  There are several reasons why it
> | > might be useful to switch from i386 to amd64:
> | >
> | >  - Most programs (though not all) will run faster, because
> | >    in amd64 mode there are twice as many general-purpose
> | >    registers, giving compilers much better opportunities
> | >    for optimizations and caching of values, and reducing
> | >    slow memory accesses.
> |
> | "twice as many" is an understatement.  AMD64 has 16 GPRs vs i386's 8 if
> | you consider BP, SI, DI and SP as GPRs (as the AMD and Intel literature
> | does); in practical terms the score is 12 to 4.
> |
> | >  - Some applications might benefit from a larger virtual
> | >    address space > 4 GB.  (Note that this is not related
> | >    to the amount of physical RAM!)
> |
> | For instance, Varnish maps its entire storage into memory, and will
> | benefit greatly from the increased address space.
> |
> | > In practice there's (almost) only one reason not to run
> | > FreeBSD/amd64 on amd64-capable hardware:  If you depend
> | > on a certain piece of software which is known not to run
> | > correctly in 64bit mode.  Fortunately those are not many.
> |
> | The only one I can think of (for a desktop) is the Flash plugin.
>
> Why?  With the nspluginwrapper we can running Linux Flash in a FreeBSD
> native browser on amd64 or i386.  With the appropriate compile foo
> or probably by getting a Linux compiled version it would work with
> a Linux browser.  Nspluginwrapper is great for running i386 plugins
> on amd64!
>
> The only thing that is preventing me from running full time on an
> amd64 kernel is the kernel support for suspend & resume.  I had to
> add a small hack the kernel to let the i386 Xserver to run on amd64.
> I need to do some more digging to answer some questions that alc had.
>
> Personally, I want to run amd64 full time so I can run and build amd64
> and i386 things on my laptop without rebooting at native speed.
>
> Doug A.

If things are setup properly with 32-/64-bit lib profiling, there should be little issue with things, unless it's dealing with kernel level drivers (i.e. nvidia-drivers, etc).

This should be true not just for nspluginwrapper, but also programs like win32-codecs, and the like, so long as the paths aren't incorrectly hardcoded when linked in the codec (haven't come across that though).

Of course you probably won't see a big performance boost for any 64-bit architectures in the codecs (SSE3, SSE4 for Intel and whatever AMD's using for their specialized FP stuff), but that's true for Windows machines as well.

-Garrett