Formal Approach for DVS-Based Power Management for Multiple Server System in Presence of Server Failure and Repair

The paper presents a DVS-based power management policy for multiprocessor systems. The aim is to optimize power consumption by keeping the job loss probability as a system-wide constraint. Optimal values for service rate are computed using an ideal setting where speed can change continuously. As real processors have discrete speed levels, we switch between two nearby speeds to achieve the optimal rate. We develop a formal model of such a system using the probabilistic model checker PRISM and prove properties satisfied by the system. We demonstrated the applicability of the policy on multiple servers and under both kinds of deadlines: DBS and DES. For a constraint value of 25%, the DBS model achieved power savings of 29.46% in theoretical, 8.75% in actual, and 7.23% in leakage power. The DES model achieved power savings of 30% in theoretical, 11.9% in actual, and 8.7% in leakage power. For robustness, a repair facility was used which can have repairmen varying from one to the total number of servers.