Star-Cap: Cluster Power Management Using Software-Only Models

Star-Cap is a high-fidelity, real-time power management system for clusters. Star-Cap´s cluster power management module uses software-only power models to implement a proactive power capping mechanism with the ability to distribute a cluster´s power budget non-uniformly across nodes. We evaluated Star-Cap on a variety of MapReduce-style workloads running on a low-power cluster. Depending on application and platform, Star-Cap improves cluster throughput by 14-43% compared to using a uniform power cap distribution policy with a purely reactive power capping mechanism, even one based on real physical measurements. Furthermore, Star-Cap maintains cluster throughput while reducing overall cluster power budget by 14% with no additional capital or operating cost. Star-Cap´s proactive power capping mechanism also improves response time to power cap violations by a factor of 2 to 10. Star-Cap´s overhead for collecting, computing, and reporting data is less than 1% CPU utilization.