[Wrf-users] Poor scalability of WRFV221 on 8-core machine

[Gerardo Cisneros]

On Thu, 2 Oct 2008, Erick van Rijk wrote:

> Hello everybody,
> I have been looking into the scalability of WRFV221 on my 8-core  
> machine and I have noticed that the scalability is very poor [...]
> 
> Do any of the user/developers want to comment on this? Any reason why  
> this is happening or point me to somewhere that can cause this  
> behaviour?
> I have build wrf221 with ifort and openmp enabled (not using MPI).

(a)  WRF scaling with OpenMP only isn't anywhere
near what can be obtained by using MPI.

(b)  Memory bandwidth per core dwindles as you
use more cores in your shared-memory machine.

Saludos,

Gerardo
-- 
Dr. Gerardo Cisneros	|SGI (Silicon Graphics, S.A. de C.V.)
Scientist             	|Av. Vasco de Quiroga 3000, Col. Santa Fe
gerardo at sgi.com		|01210 Mexico, D.F., MEXICO
(+52-55)5563-7958 	|http://www.sgi.com/