[Beowulf] MPICH on heterogeneous (i386 + x86_64) cluster

[Sean Dilda]

John Lau wrote:
> Hi,
> 
> Have anyone try running MPI programs with MPICH on heterogeneous cluster
> with both i386 and x86_64 machines? Can I use a i386 binary on the i386
> machines while use a x86_64 binary on the x86_64 machines for the same
> MPI program? I thought they can communicate before but it seems that I
> was wrong because I got error in the testing.
> 
> Have anyone try that before?

I've not tried it, but I can think of a few good reasons why you'd want 
to avoid it.  Lets say you want to send some data that's stored in a 
long from the x86_64 box to the x86 box.  Well, on the x86_64 box, a 
long takes up 8 bytes.  But on the x86 box, it only takes 4 bytes.  So, 
chances are some Bad Stuff(tm) is going to happen if you try to span an 
MPI program across architectures like that.

On the other hand, the x86_64 box will run x86 code without a problem. 
So i suggest running x86 binaries (and mpich) libraries on all of the 
boxes.  While I haven't tested it myself, I can't think of any reason 
why that wouldn't work.