Feasibility test for real-time communication using wormhole routing

Real-time applications are becoming increasingly demanding in terms of the computational power and the I/O bandwidth required. Massively parallel computers using 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 need to be developed to ensure that critical hard-deadline messages meet their deadlines. An off-line 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 packetising long messages increases the overall schedulability of the network