64 Bit Questions

[Anthony Dematteo]

I have a couple questions about the AMD64 Project.

1.  They page mentions that there is multiprocessor support.  Does
this include the dual core processors?  Will the OS dispatch processes
and threads to each core?

2.  While the OS will use the 64 bit mode, will the applications still
run in the compatibly mode?  Will the applications still only use 32
bits.

3. Also, will the OS take advantage of being 64 bit and load itself
into memory higher than the 32 bit addressable mark so that my 32 bit
applications can use the lower part?

4. If I enable 64 bit compilation on GCC prior to installing a port,
will the port then be 64 bit enabled?

5. If I stall an IDE and write my own applications on a 64 bit
machine, can a 32 bit machine still run them?


Thank you in advance for your response and time.

Anthony DeMatteo
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Re: 64 Bit Questions

[Albert Shih]

 Le 18/01/2006 à 17:40:00-0500, Anthony Dematteo a écrit
> I have a couple questions about the AMD64 Project.
> 
> 1.  They page mentions that there is multiprocessor support.  Does
> this include the dual core processors?  Will the OS dispatch processes
> and threads to each core?

I only can answer this question :

I've try to install FreeBSD 6.0-Release AMD64 on dual opteron 275 (dual core).

Everething work fine and we have 4 proc in the OS. 

Unfortunaly I do not have the chance to launch 4 big process to see the
thread performance. For example I known on dual-core PowerPC Apple
Macintosh 
time(4 x proccess)=time(1x process) [For the same process of course)


Regards.


--
Albert SHIH
Universite de Paris 7 (Denis DIDEROT)
U.F.R. de Mathematiques.
Heure local/Local time:
Thu Jan 19 00:52:28 CET 2006
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Re: 64 Bit Questions

[Giorgos Keramidas]

On 2006-01-18 17:40, Anthony Dematteo <[EMAIL PROTECTED]> wrote:
> I have a couple questions about the AMD64 Project.
>
> 1.  They page mentions that there is multiprocessor support.  Does
> this include the dual core processors?  Will the OS dispatch processes
> and threads to each core?

Not sure if I'm the right person to answer this in great technical
detail, but I think the answer is 'yes' to both questions.

> 2.  While the OS will use the 64 bit mode, will the applications still
> run in the compatibly mode?

Not necessarily.  By default the "base system" and any applications you
compile yourself will be 64-bit too.  The installed compiler and
toolchain support building 32-bit binaries too, if you manually compile
things yourself, but you don't have to if you don't feel like doing it.

> Will the applications still only use 32 bits.

No, 64-bit applications can use the full 64-bit address range.

> 3. Also, will the OS take advantage of being 64 bit and load itself
> into memory higher than the 32 bit addressable mark so that my 32 bit
> applications can use the lower part?

I'm not sure if I understand the question correctly, but why does the
specific 'place' in the virtual 64-bit address space matter to an
application?  Some may argue that depending on such low level
information is broken behavior and should be fixed in the application.

> 4. If I enable 64 bit compilation on GCC prior to installing a port,
> will the port then be 64 bit enabled?

Ports do not support cross-compiling, as far as I know.  If you build on
a 64-bit machine, you get 64-bit binaries.  If you build on a 32-bit
machine, you get 32-bit binaries.

> 5. If I stall an IDE and write my own applications on a 64 bit
> machine, can a 32 bit machine still run them?

No.  The 64-bit binaries refer to registers, addresses and other parts
of the 64-bit architecture that are not available in 32-bit hardware.

The other way around works fine though.  The 64-bit versions of FreeBSD
include 32-bit libraries and runtime support too, so you can run 32-bit
binaries seamlessly.  In fact, this is exactly what enabled me to run a
32-bit binary of CMUCL, and experiment with LISP now that I've started
learning about it:

[EMAIL PROTECTED]:/home/keramida$ uname -v
FreeBSD 7.0-CURRENT #0: Mon Jan 16 17:28:28 EET 2006 \
[EMAIL PROTECTED]:/home/build/obj/home/build/src/sys/FLAME

[EMAIL PROTECTED]:/home/keramida$ which lisp
/usr/local/bin/lisp

[EMAIL PROTECTED]:/home/keramida$ file `!!`
file `which lisp`
/usr/local/bin/lisp: ELF 32-bit LSB executable, Intel 80386, \
version 1 (FreeBSD), for FreeBSD 6.0 (600100), \
dynamically linked (uses shared libs), not stripped

[EMAIL PROTECTED]:/home/keramida$ lisp
; Loading #P"/home/keramida/init.lisp".
CMU Common Lisp 19c Release (19C), running on flame.pc
With core: /usr/local/lib/cmucl/lib/lisp.core
Dumped on: Wed, 2005-11-30 01:04:28+02:00 on boomerang
See  for support information.
Loaded subsystems:
Python 1.1, target Intel x86
CLOS based on Gerd's PCL 2004/04/14 03:32:47
*

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