pNetCDF and OpenMP?

[Wei-keng Liao]

Hi, John,

We have not yet tested pnetcdf under the MPI-OpenMP hybrid programming environment.
Could you please describe more in detailed on how your program makes pnetcdf calls?
Or provide us a sample program that can re-produce the hanging?
Did you see the same hanging happened when using a different file system?
Have you tried run one OpenMP thread per MPI process and seen the same problem?

Wei-keng


On Oct 10, 2011, at 7:17 AM, John Michalakes wrote:

> I'm running into a case where WRF reads and writes through pNetCDF okay when compiled and running in MPI-only mode, but hangs when running hybrid MPI/OpenMP mode.  This is on a Lustre file system.  Application executable is compiled and linked using Intel compilers and OpenMPI.  The system is NREL's RedMesa Sun Blade Linux cluster (a part of Sandia's Red Sky: http://www.top500.org/system/10188 ).  Are there reports of problems combining pNetCDF on Lustre with threaded MPI applications?  Thanks, -John
> 
> -- 
> John Michalakes
> National Renewable Energy Laboratory
> 1617 Cole Blvd.
> Golden, Colorado 80401
> Phone: 303-275-4297
> Fax: 303-275-4091
> http://www.nrel.gov/csc/staff_michalakes.html
>