Integrating communication protocol selection with hardware/software codesign

This paper explores the problem of determining the characteristics of the communication links in a computer system as well as determining the best functional partitioning. In particular, we present a communication estimation model and show, by the use of this model, the importance of integrating communication protocol selection with hardware/software partitioning. The communication estimation model allows for fast estimation but is still sufficiently detailed as to allow the designer or design tool to efficiently explore tradeoffs between throughputs, bus widths, burst/nonburst transfers, operating frequencies of system components such as buses, CPU’s, ASIC’s, software code size, hardware area, and component prices. A distinct feature of the model is the modeling of driver processing of data (packing, splitting, compression, etc.) and its impact on communication throughput. The integration of communication protocol selection and communication driver design with hardware/software partitioning is illustrated by a number of design space exploration experiments carried out within the LYCOS cosynthesis system, using models of the PCI and USB protocols.