Analyzing the Real-Time Properties of a Dataflow Execution Paradigm using a Synthetic Aperture Radar Application

Real-time signal processing applications are commonly designed using a dataflow software architecture. Here we attempt to understand fundamental real-time properties of such an architecture — the Navy’s coarse-grain Processing Graph Method (PGM). By applying recent results in real-time scheduling theory to the subset of PGM employed by the ARPA RASSP Synthetic Aperture Radar benchmark application, we identify inherent real-time properties of nodes in a PGM dataflow graph, and demonstrate how these properties can be exploited to perform useful and important system-level analyses such as schedulability analysis, end-to-end latency analysis, and memory requirements analysis. More importantly, we develop relationships between properties such as latency and buffer bounds and show how one may be traded-off for the other. Our results assume only the existence of a simple EDF scheduler and thus can be easily applied in practice.