[geeks] Game GPU clusters for supercomputering

[Joshua Boyd]

On May 22, 2008, at 10:16 PM, Shannon Hendrix wrote:

> On May 22, 2008, at 15:37 , Sandwich Maker wrote:
>
>
>> i read a news item not too long ago, about how sony had given
>> umass-dartmouth a dozen ps3s, and the astrophysics dept had them
>> running linux in a cluster doing supercomputer work.  that of course
>> says nothing as to whether sony runs linux on them.
>>
>> i also just read that one of sony's new lcd dtvs runs linux inside.
>
> Everything I have read suggests that it is cheaper to just get  
> IBM's blade servers, depending on how much power you need.

And of course, you can get Cell blades from IBM and Mercury.

> On a related note, nVidia now sells GPU clusters.

Well, they aren't very self sufficient.  I suspect that on average  
you need a 1U computer for each 1U of GPUs, and I think 1U of GPUs  
means something like 4 of them.  Now each of those 4 has an insane  
number of cores, and each core has an insane number of hardware  
contexts for doing something like hyper threading.  Basically, it  
looks like a 512 vector processors.

The GPU stuff is cool looking, but there are a lot of things I like  
better about the Cells.  The Cells seem a bit more straight forward  
to program.  The Cells can take a lot more memory (first generation  
is 2 gigs per chip instead of 1.5 gigs, but the new model that just  
started shipping can take 32gigs per chip).  The Cells don't require  
a PC next to them.  And long term most importantly, the Cells seem to  
be much better in the documentation department.  With Nvidia, your  
choices are Cg, GLSL, or the CUDA C compiler.  The machine details  
aren't publicly documented.  With the Cell you have a lot of  
documentation and you have GCC, which means you have C, C++,  
Objective C, Fortran, and ADA.  I'm not sure that C++, Objective C or  
Ada are practical on the SPUs, but Fortran has got to be a big deal  
for a lot of people.  Oh, and we have assembly.  And having assembly  
means that we can get a lot more languages for it.