Supporting parallel applications on clusters of workstations: The intelligent network interface approach

This paper presents a novel networking architecture designed for communication intensive parallel applications running on clusters of workstations (COWs) connected by high speed network. This architecture permits: (1) the transfer of selected communication-related functionality the host machine to the network interface coprocessor and (2) the exposure of this functionality directly to applications as instructions of a Virtual Communication Machine (VCM) implemented by the coprocessor. The user-level code interacts directly with the network coprocessor as the host kernel only `connects´ the application to the VCM and does not participate in the data transfers. The distinctive feature of our design is its flexibility: the integration of the network with the application can be varied to maximize performance. The resulting communication architecture is characterized by a very low overhead on the host processor by latency and bandwidth close to the hardware limits, and by an application interface which enables zero-copy messaging and eases the port of some shared-memory parallel applications to COWs. The architecture admits low cost implementations based only on off-the-shelf hardware components. Additionally, its current ATM-based implementation can be used to communicate with any ATM-enabled host