[RegCNET] RegCM3 on multiple cores

[XUNQIANG BI]

Hi, Ramses:

It's doable, I think.

The good news is that the present parallel RegCM code works with the
Duo-core or Quad-core. (For Quad-core, I haven't found one to have a test,
but I guess that it's doable).

Actually I have just had the implementation of openmpi in my Duo-core
laptop yesterday, and I can submit the parallel job on 2 CPU (or 1 CPU).

And the benchmark:     (150x102L18, 20km resolution, 4 day integration)

by using 1 CPU, it takes     55 minutes
by using 2 CPU, it takes     34 minutes.

I ma using the openmpi created by (gcc, g++, and ifort version 11).

The bad news id that I cannot get exactly the same result in the above
two runs, (I'll try to reduce the optimalization option to see if I could
make it).

Regards,
Xunqiang Bi

On Tue, 10 Mar 2009, Ramses Russel Sol wrote:

> Dear RegCM users,
>
> Hi! I am a Research Assistant at the Manila Observatory and we are
> interested in using RegCM3 to provide accurate and timely forecasts of the
> weather in the Philippines. In line with this, we are interested in running
> RegCM3 using Intel's Core2 Quad technology.
>
> I read in the archives that RegCM3 does not support -Mconcur
> Auto-parallelization Option nor does it support OpenMP, according to a reply
> from Dr. Xunqiang Bi on January 15, 2007. In the same e-mail, he also said
> that the Parallel Version of RegCM3 just works with MPI (MPICH, LAM MPI, or
> MPI library provided by computer vendor). On November 25, 2008, Dr. Bi also
> said that RegCM3 works with OpenMPI and that it is better than MPICH. But
> all these utilize muliple processors or clusters rather than multiple core
> processors. I also saw other e-mails asking whether RegCM3 can be run using
> multicore technology and it seems that they weren't successful either.
>
> Since most of these queries and/or emails are already old, I would just like
> to ask if the present RegCM3 already has support for Ifort's -openmp option.
> If it doesn't, is there any way for me to be able to utilize the 4 processor
> cores so as to lessen the time of the runs using RegCM3?
>
> Thank you very much in advance!
>
>
>
> Respecfully,
>
> Ramses Russel d. J. Sol
> Project Research Assistant
>
> Regional Climate Systems
> Manila Observatory
> Ateneo de Manila Campus, Loyola Heights
> Quezon City, Philippines
>

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   Dr. Xunqiang Bi         email:bixq at ictp.it
   Earth System Physics Group
   The Abdus Salam ICTP
   Strada Costiera, 11
   P.O. BOX 586, 34100 Trieste, ITALY
   Tel: +39-040-2240302  Fax: +39-040-2240449
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~