OCaml on ppc64 (Linux)?

OCaml on ppc64 (Linux)?

[Richard Jones]

Does anyone know of the status of OCaml on ppc64 on Linux?

It's a secondary Fedora platform and therefore I'd like to support it.
Someone at Red Hat did some work on trying to port it, but it was
still quite broken AIUI:

  http://git.infradead.org/?p=users/dwmw2/ocaml-ppc64.git

Is there anything we can do to help it along (eg. hardware purchase or
also we can give out limited accounts on a PPC64 machine)?

Rich.

-- 
Richard Jones
Red Hat

Re: [Caml-list] OCaml on ppc64 (Linux)?

[Xavier Leroy]

> Does anyone know of the status of OCaml on ppc64 on Linux?
> It's a secondary Fedora platform and therefore I'd like to support it.
> Someone at Red Hat did some work on trying to port it, but it was
> still quite broken AIUI:

Right. I followed David Woodhouse's attempts from a distance.  While
PPC64/MacOSX (supported in OCaml 3.10) is a small change from PPC32/MacOSX,
there are significant differences between PPC64/Linux and PPC32/Linux
-- or for that matter PPC64/Linux and all other PPC platforms.

> Is there anything we can do to help it along (eg. hardware purchase or
> also we can give out limited accounts on a PPC64 machine)?

My initial reaction was to conclude that PPC64 isn't worth the porting
effort: Apple killed the PowerPC architecture on the desktop, and
while PowerPC is still strong in the embedded world, it's in 32-bit
mode.  Then someone told me that the Playstation 3 is a PPC64/Linux
platform...  I'm still not quite sure whether having OCaml on
PPC64/Linux is worth the effort, even if we had the corresponding hardware.

- Xavier Leroy

Re: [Caml-list] OCaml on ppc64 (Linux)?

[Adrien]

2007/10/24, Xavier Leroy <Xavier.Leroy@inria.fr>:
Then someone told me that the Playstation 3 is a PPC64/Linux
> platform...  I'm still not quite sure whether having OCaml on
> PPC64/Linux is worth the effort, even if we had the corresponding hardware.

PlayStation3's processor (the Cell) has some parenty with powerpc but
it mostly has differences (cell is a ppc6). It has many cores and in
fact a variable number of more-or-less specialized cores.
It's a sort of revolution because its SMP capabilities are really
different from thos of a Core2Duo or of an Athlon64X2. I think there
is at least a theorical interest as it seems to perfectly fit
simultaneous processing (but maybe not so close).

There is of course wikipedia's article :
http://en.wikipedia.org/wiki/Cell_microprocessor
It shows Cell should make its way in super-computing.

But more striking are examples of cell's power and scalability (at
least apparent):
http://www.spectrum.ieee.org/print/4837
http://www.rapidmind.net/case-studies.php

I don't know of any recent and proper independant benchmarks but when
I first read about it, Cell looked like a thing we should keep an eye
on.


 ---

Adrien Nader

Re: [Caml-list] OCaml on ppc64 (Linux)?

[Gordon Henriksen]

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On Oct 24, 2007, at 15:29, Adrien wrote:

> 2007/10/24, Xavier Leroy <Xavier.Leroy@inria.fr>:
>
>> Then someone told me that the Playstation 3 is a PPC64/Linux  
>> platform...  I'm still not quite sure whether having OCaml on  
>> PPC64/Linux is worth the effort, even if we had the corresponding  
>> hardware.
>
> PlayStation3's processor (the Cell) has some parenty with powerpc  
> but it mostly has differences (cell is a ppc6). It has many cores  
> and in fact a variable number of more-or-less specialized cores.  
> It's a sort of revolution because its SMP capabilities are really  
> different from thos of a Core2Duo or of an Athlon64X2. I think  
> there is at least a theorical interest as it seems to perfectly fit  
> simultaneous processing (but maybe not so close).

The SPUs are quite unique, but the PPU (the likely target of an Ocaml  
implementation) is a fairly ordinary PowerPC.

— Gordon


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Re: [Caml-list] OCaml on ppc64 (Linux)?

[Christophe Raffalli]

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Gordon Henriksen a écrit :
> On Oct 24, 2007, at 15:29, Adrien wrote:
>
>> 2007/10/24, Xavier Leroy <Xavier.Leroy@inria.fr
>> <mailto:Xavier.Leroy@inria.fr>>:
>>
>>> Then someone told me that the Playstation 3 is a
>>> PPC64/Linux platform...  I'm still not quite sure whether having
>>> OCaml on PPC64/Linux is worth the effort, even if we had the
>>> corresponding hardware.
>>
>> PlayStation3's processor (the Cell) has some parenty with powerpc
>> but it mostly has differences (cell is a ppc6). It has many cores and
>> in fact a variable number of more-or-less specialized cores. It's a
>> sort of revolution because its SMP capabilities are really different
>> from thos of a Core2Duo or of an Athlon64X2. I think there is at
>> least a theorical interest as it seems to perfectly fit simultaneous
>> processing (but maybe not so close).
>
> The SPUs are quite unique, but the PPU (the likely target of an Ocaml
> implementation) is a fairly ordinary PowerPC.

not so fairly ordinary:

It has an in-order execution model (so it is very simple to free enough
room for the PPU), but it seems not to impact performance.
And it has a single precision floating point unit which is ultra fast
(15 times faster than the double precision unit of an intel chip).

For some specific numerical code, report achieve around 6 times the
speed of an intel chip by representing floats as a pair with a single
precision and a double precision approximation (doing the first
iteration using simple precision). ... Why did apple moved to intel ?

So guess what you would get using the SPUs ...

>
> — Gordon
>
> ------------------------------------------------------------------------
>
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-- 
Christophe Raffalli
Universite de Savoie
Batiment Le Chablais, bureau 21
73376 Le Bourget-du-Lac Cedex

tel: (33) 4 79 75 81 03
fax: (33) 4 79 75 87 42
mail: Christophe.Raffalli@univ-savoie.fr
www: http://www.lama.univ-savoie.fr/~RAFFALLI
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