[cam-users] using SMP+SPMD mode on a Linux cluster

Chul Eddy Chung cchung@fiji.ucsd.edu
Wed, 21 May 2003 11:41:23 -0700


Dear  CAM2.0.1 users,

I am trying to run CAM2.0.1 in the SMP+SPMD mode on my cluster (RedHat 
Linux 7.1 and PGI/CDK4.1) that has 8 nodes and 16 CPUs (2 CPUs in each 
node).  I have been successfully running the CAM2.0.1 in the pure SPMD 
mode (16 CPUs and 16 MPI jobs).  Following Steve Ghan's suggestion, I 
modified "Makefile" as below (in order to do SMP+SPMD):
----- Makefile -----
 ifeq ($(SMP),TRUE)
   FFLAGS += -mp
   LDFLAGS += -mp -Bstatic
 endif
-------
Without the above modification (-Bstatic), CAM2.0.1 does not even run 
for a second.  It gives me "segmentation fault" error immeidately.  With 
the above modification, it runs for a few seconds and stops giving me 
the following error message:

----------
uccessfully initialized the land model
begin initial run at:
   nstep=             0  year=             0  month=             9  day= 
           1  seconds=             0

************************************************************

SSTINI: Read sst data for dates           816        43200  
and           916
           0
ICEINI: Read ice data for dates           816        43200  
and           916
           0
Segmentation fault
Segmentation fault
0: DEALLOCATE: memory at c6de730 not allocated
-------------

Does anybody have any idea?  If so, how did you resolve it?  Before 
running CAM2, I modified .cshrc to add "setenv  OMP_NUM_THREADS 2" on 
each node.

-- 
Chul Eddy Chung: Assistant Project Scientist
Scripps Institution of Oceanography, UCSD
Tel: 858-822-1356   Fax: 858-534-7452