Energy-aware standby-sparing for fixed-priority real-time task sets

• A standby-sparing solution that achieves high reliability for real-time embedded systems with low energy-consumption is presented.
• The solution targets common periodic fixed-priority task systems.
• Our framework has both static and dynamic components; and it is experimentally shown to provide significant gains in terms of energy and reliability.

For mission- and safety-critical real-time embedded systems, energy efficiency and reliability are two important design objectives that must be often achieved simultaneously. Recently, the standby-sparing scheme that uses a primary processor and a spare processor has been exploited to provide fault tolerance while keeping the energy consumption under control through DVS and DPM techniques. In this paper, we consider the standby-sparing technique for fixed-priority periodic real-time tasks. We propose a dual-queue mechanism through which the executions of backup tasks are maximally delayed, as well as online algorithms to manage energy consumption. Our experimental results show that the proposed scheme provides energy savings over time-redundancy based techniques while offering reliability improvements.