[vtkusers] paralleliso isnt.

[Stanley Dunn]

On Mon, 20 Aug 2001, Berk Geveci wrote:

> When I ran this program in our cluster, I also observed that it scales
> very poorly. I think there are two reasons for this:
> 1) IO: In our setting, the data files are on a shared disk which is mounted
> via NFS. All processes start reading from the same disk, sharing the same
> network switch. To test whether this is the case, one would have to put a
> local copy of the data files to each machine.
> 2) Balance: This problem is not balanced AT ALL. Some of the processes
> do not generate anything when contouring, some others generate a lot. The
> situation gets worse as the number of processes is increased.

When I was working on this last year with Scott Klasky at PPPL, it did
scale very poorly and I believe that this is due in part to 
marshalling/unmarshalling the data.  I assume that the
marshalling/unmarshalling has not changed in the past year.
Stan

 
Stanley M Dunn, Ph.D.
Paul S. and Mary W. Monroe Faculty Scholar
Vice Chair, Biomedical Engineering
Associate Dean for Industrial Outreach, School of Engineering
Rutgers University

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