Feedback-Based Energy Management in a Standby-Sparing Scheme for Hard Real-Time Systems

The interaction between fault tolerance and energy consumption is an interesting avenue in the realm of designing embedded systems. In this paper, a scheme for reducing energy consumption in conventional standby-sparing systems is introduced. In the proposed method, the primary unit exploits dynamic voltage scaling (DVS) and dynamic power management (DPM) is employed for the spare unit. The framework which is used in the primary unit is composed of a feedback system to follow up workload along with a three-layer yet light-weight energy manager which guarantees hard real-time constraints of the system. Moreover, an optimal approach (but not practical) as a margin for the minimum energy consumption of this system is presented and the capability of other methods in reducing energy consumption is compared. Simulation results show an improvement in energy saving as compared with previous works and also show that the proposed method is near optimal for task sets with different dynamic workloads.