Re: [Swarm-Modelling] SWARM on Clusters

[Marcus G. Daniels]

Sunwoo Park wrote:

> I just joined in this mailing list.
> I have a simple question regarding SWARM software.
> Is there any SWARM implementation that runs on cluster machines (or MPP
> machines) based on Message Passing Paradigm (e.g., MPI) ?
>  
Swarm has a fine-grained knowledge of concurrency during a simulation.  
When multiple agents do something at the same timestep, Swarm knows 
this.   But that's just a little atom of the whole simulation execution 
sequence.  What this means is that in order for Swarm to exploit this 
knowledge on a parallel computer, it is necessary to be able to 
efficiently get that atom of computation to a physical processor.  A 
cluster, like a Beowulf arrangement of PCs, can't do this because the 
communication expense of getting the atom to the processor not amortized 
by the computation done.   A SMP or NUMA system can do this because the 
communication/overhead expense of getting the computation to the 
processor is small.  So if you have a two or four or eight way Opteron 
or Sun system or a big NUMA system like a SGI Altix, the interconnect 
between processors could reasonably slurp up these atoms and there would 
be a scalability win.

I think it would be hard to make a message passing system scale very 
well based on an architecture like Swarm.   You'd need low-latency 
interconnect, maybe Myrinet.

In any case, Swarm doesn't implement either.  A multithreaded Swarm 
would be feasible, but would assume a shared memory system like I mentioned.