Current Bottlenecks In The Scalability Of Openfoam On Massively Parallel Clusters
Massimiliano Culpo · Zenodo (CERN European Organization for Nuclear Research) · 2012
The scaling behavior of different OpenFOAM versions is analyzed on two benchmark problems. Results show that the applications scale reasonably well up to a thousand tasks. An in-depth profiling identifies the calls to the MPI_Allreduce function in the linear algebra core libraries as the main communication bottleneck. A sub-optimal performance on-core is due to the sparse matrices storage format that does not employ any cache-blocking mechanism at present. Possible strategies to overcome these limitations are proposed and analyzed, and preliminary results on prototype implementations are presented.