Real-time interprocessor communication for point-to-point networks using wormhole routing

Real time applications are becoming more and more demanding in terms of the computational power needed and the I/O bandwidth required. Massively parallel computers using wormhole routing are the most promising architectures to deliver scalable computational power efficiently. It follows that real time applications will want to take advantage of these architectures. However before real time applications can exploit massively parallel architectures, mechanisms to ensure that critical hard deadline messages meet their deadlines need to be developed. An offline feasibility test for real time wormhole routed messages is presented. The test will work for any static priority assignment scheme. The effectiveness of several proposed priority assignment methods is evaluated using random (uniform) traffic patterns. Simulations using a flit level simulator (FLS) are performed to validate the test. Simulations show that a high degree of schedulability can be achieved with a finite number of virtual channels, and that packetizing long messages increases the overall schedulability of the network.