COWLS: Hardware-Software Cosynthesis of Wireless Low-power Distributed Embedded Client-Server Systems

In this paper, we present COWLS, a hardware-software cosynthesis algorithm that targets embedded systems composed of servers and low-power clients that communicate with each other through a channel of limited bandwidth, e.g., a wireless link. A novel scheduling algorithm is used to pipeline the execution of tasks that serve multiple clients associated with a given server. COWLS simultaneously optimizes the price of the client-server system, the power consumption of the clients, and the response times of tasks that have only soft deadlines, while meeting all of the hard deadlines. It produces numerous solutions that trade off different architectural features, e.g., price, power consumption, and response time, of an embedded client-server system. As far as we know, this is the first synthesis algorithm of its kind. We present the experimental results for numerous pseudorandom examples, a low-power client-server camera system, as well as the rest of the benchmarks within a publicly released embedded system synthesis benchmark suite.