Hints on improving performance with WRF and Pnetcdf

[Craig Tierney]

On 9/2/10 6:15 PM, Rob Latham wrote:
> On Thu, Sep 02, 2010 at 04:27:42PM -0600, Craig Tierney wrote:
>> Is it possible to set hints from the environment
>> without having to explicitly call MPI_Info_set?
>> It appears that Cray has done this, but I didn't
>> find anything in the ROMIO documentation that indicates
>> it has been done here.
>
> Hi Craig
>
> Can you tell me more about the Cray mechanism?
>
> I added this to ROMIO a few releases back (MPICH2-1.0.6 and newer) ,
> maybe that's what they are using:
>
> http://www.mcs.anl.gov/research/projects/romio/doc/users-guide/node13.html
>
> ==rob
>

I am not using a Cray, but I found this information:

http://www.nersc.gov/vendor_docs/cray/intro_mpi.htm

Look for MPICH_MPIIO_HINTS

I did try setting the hints myself by changing the code, and performance
still stinks (or is no faster).  I was just looking for a way to not
have to modify WRF, or more importantly have every user modify WRF.

The global settings that you have aren't going to work.  We support
both Panasas and Lustre, and their settings are probably going to be
different.

Thanks,
Craig