[mpich-discuss] halo update performance comparison

[Rajeev Thakur]

> Is there room for improvement?

Yes, we are looking into it.

Rajeev

On Dec 13, 2013, at 2:31 PM, "Kokron, Daniel S. (GSFC-610.1)[Computer Sciences Corporation]" <daniel.s.kokron at nasa.gov> wrote:

> All,
> 
> I have been interested in MPI datatypes since reading about them and playing with the benchmark found at http://unixer.de/research/datatypes/ddtbench/
> 
> I am working with a weather model that spends considerable time doing halo (aka ghost cell) updates.  The existing code uses irecv/isend.  Since most of the time spent doing halo updates is actually spent packing and unpacking the MPI buffers, I was hoping the use of datatypes would improve performance.  Unfortunately, the datatype version is actually quite a bit slower than the standard non-blocking pt2pt code.  I found this to be that case for both mpich-3.1rc1 and a recent version of a vendor MPI implementation (not MPICH based).  I have not run this comparison using OpenMPI.
> 
> Is data type performance an active area of development?  Is there room for improvement?
> 
> Daniel Kokron
> NASA Ames (ARC-TN)
> SciCon group
> 301-286-3959
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