Performance analysis and optimization of mixed asynchronous synchronous systems

This paper deals with the system-level performance analysis and optimization of a class of digital systems we call mixed asynchronous-synchronous systems. In such a system, each computation module is either synchronous or asynchronous. The communication between all the modules is assumed to be data-driven. In order to adequately describe the timing of such architectures, we introduce a graph model called MASS which is based on several extensions of timed marked graphs. The rst extension is that the node set V is partitioned into synchronous and asynchronous nodes. A synchronous node can only re at ticks of its local module clock. Based on these extensions, we analyze the behavior of MASS, in particular period, periodicity and maximal throughput rate. Finally, we introduce the optimization problem of assigning appropriate clock phases to synchronous nodes so to maximize the throughput rate of the resulting system. An exact solution as well as a polynomial time algorithm for nearly optimal phase assignment are presented.