Schedulability-driven performance analysis of multiple mode embedded real-time systems

Providing multiple modes to support dynamically changing environments, standards, and new services is prevalent in embedded systems, especially in mobile radio systems. Because such a system frequently contains time-constrained tasks, it is important to analyze the temporal requirements as well as the functional correctness. This paper presents a method to analyze temporal requirements imposed on an embedded real-time system supporting multiple modes. While most performance analysis methods focus only on testing the feasibility of a task or a system, our method goes further by addressing the problem of locating hot spots of a system thereby helping the designer to choose among alternative designs or architectures. We formally define the analysis problem and show that it is very unlikely to be solved efficiently. We present a heuristic algorithm, which is accurate and fast enough to be used in iterative processes in system-level analysis and design. The analysis problem is extended to accommodate probabilistic behavior exhibited by soft real-time tasks.