how many nodes are in your cluster?

[Greg Lindahl]

On Sun, Jul 07, 2002 at 05:47:41PM -0400, Dan Sturtevant wrote:

> It seems that when many people design their cluster they tend to build 
> them with a power of 2 number of compute nodes.  Is this just because we 
> are all used to thinking in binary or are there codes (not benchmarks) 
> that require or optimize for N=2^m nodes/procs?  If so, what are you 
> running?

In my days of benchmarking real codes, I have only rarely run into
codes which actually only run on N^2 cpus. The most common
decompositions, however, are 1D and 2D, which may not map that well
into the problem sizes you'd like to run.

Bigger clusters, by the way, usually run more than one job, which
makes the issue of "how many cpus can I use for a single job" not as
relevant to how big your cluster is.

A number of Myrinet clusters have 512 nodes, but that's a break point in
Myrinet's price scaling.

greg