MPI derived data types support in VIRTUS

The VIRTUal System (VIRTUS) project is focused on providing advanced features for high performance communication and I/O in cluster environments. In this paper we report our experience in porting MPICH 1.1.x atop the Fast Messages library and how we used the features of FM to provide efficient communication for non-contiguous data structures. The porting concerned two different internal interfaces of MPICH 1.1.x called channel and ADI-2, respectively. The ADI-2 interface offers a rich set of primitives that allow the implementation of communication support to MPI derived data types. We present extensive experimental data gathered on Solaris, Linux and WinNT platforms that show how the ADI-2 interface achieves the same performance levels of FM for contiguous and non-contiguous data. These results confirm the effectiveness of FM’s interface and implementation in delivering the raw hardware performance of the communication subsystem to the applications.