Configuring the Circuit Switched Tree for Multiple Width Communications

Dynamically reconfigurable architectures offer extremely fast solutions to various problems. The Circuit Switched Tree (CST) is an important interconnect used to implement such architectures. A CST consists of processing elements (PEs) and switches. PEs communicate among themselves using the links of the tree. A key component for successful communication is scheduling individual communications and the configuration of the CST switches. This paper presents a scheduling and configuration algorithm for communications on a CST where conflicts force multiple rounds of routing to perform all communications. The paper also explains how to apply the algorithm to two important classes of communications, well-nested and monotonic, for which the algorithm is optimal and efficient. The algorithm is distributed and requires only local knowledge, yet it captures the global picture to ensure proper communication.