MPICH-GQ: quality-of-service for message passing programs

Parallel programmers typically assume that all resources required for a program's execution are dedicated to that purpose. However, in local and wide area networks, contention for shared networks, CPUs, and I/O systems can result in significant variations in availability, with consequent adverse effects on overall performance. The authors describe a new message-passing architecture, MPICH-GQ, that uses quality of service (QoS) mechanisms to manage contention and hence improve performance of message passing interface (MPI) applications. MPICH-GQ combines new QoS specification, traffic shaping, QoS reservation, and QoS implementation techniques to deliver QoS capabilities to the high-bandwidth bursty flows, complex structures, and reliable protocols used in high-performance applications--characteristics very different from the low-bandwidth, constant bit-rate media flows and unreliable protocols for which QoS mechanisms were designed. Results obtained on a differentiated services testbed demonstrate their ability to maintain application performance in the face of heavy network contention