[Beowulf] Performance characterising a HPC application

[Greg Lindahl]

On Wed, Mar 21, 2007 at 06:41:07AM -0400, Scott Atchley wrote:

> I have not benchmarked any applications that need more than 250 MB/s  
> during computation,

There is a large class of computations which alternate non-overlapped
compute and communicate cycles. The average over the lifetime of the
process can be ~ 100 MB/s, but that could easily mean it is sending
at 1 GByte/s for 10% of the runtime. If you slow down communications
by a factor of 4, the app will run a lot slower.

-- greg