Reliability-aware Dynamic Voltage Scaling for energy-constrained real-time embedded systems

The dynamic voltage scaling (DVS) technique is the basis of numerous state-of-the-art energy management schemes proposed for real-time embedded systems. However, recent research has illustrated the alarmingly negative impact of DVS on task and system reliability. In this paper, we consider the problem of processing frequency assignment to a set of real-time tasks in order to maximize the overall reliability, under given time and energy constraints. First, we formulate the problem as a non-linear optimization problem and show how to obtain the static optimal solution. Then, we propose on-line (dynamic) algorithms that detect early completions and adjust the task frequencies at run-time, to improve overall reliability. Our simulation results indicate that our algorithms perform comparably to a clairvoyant optimal scheduler that knows the exact workload in advance.