Awareness of MPI Virtual Process Topologies on the Single-Chip Cloud Computer

This paper presents an approach to improve the communication bandwidth between MPI tasks by evaluating the application´s communication graph and making optimal use of communication buffers. It was implemented on the Intel Single-Chip Cloud Computer (SCC). The SCC is a processor with 48 cores created by Intel Labs. Special to the SCC is the SRAM-based Message Passing Buffer which can be used as fast communication memory. First, we evaluate RCKMPI, the MPI implementation for the SCC which makes use of this MPB. Then we extend RCKMPI to support virtual process topologies like defined in the MPI specification. The presented approach shows a performance improvement up to 44 % for a communication-intensive application.