Reliability-Aware Dynamic Energy Management in Dependable Embedded Real-Time Systems

Recent studies show that, voltage scaling, which is an efficient energy management technique, has a direct and negative effect on system reliability because of the increased rate of transient faults (e.g., those induced by cosmic particles). In this work, we propose schemes that explore dynamic slack for energy savings while taking system reliability into consideration. The proposed schemes dynamically schedule an additional recovery to recuperate the reliability loss due to energy management. Based on the amount of available slack, the application size and the fault rate changes, we analyze when it is profitable to reclaim the slack for energy savings without sacrificing system reliability. Checkpoint technique is further explored to efficiently use the slack. Analytical and simulation results show that, the proposed reliability-aware energy management schemes can achieve comparable energy savings as ordinary energy management schemes while preserving system reliability. The ordinary energy management schemes that ignore the effects of voltage scaling on fault rate changes could lead to drastically decreased system reliability.