Accurate and Low-Overhead Process-Level Energy Estimation for Modern Hard Disk Drives

Measuring the energy consumed by modern secondary storage devices and attributing it to the causative application´s processes can guide optimization of application energy efficiency. Prior work has focused on hard disk drive or file system energy management using custom-built measurement systems and models, but suffers from limitations that prohibit the attribution of the hardware energy consumption to the causative processes. This paper presents a novel process-level disk drive energy estimation system that monitors the operating system kernel to predict the storage power consumption created by individual processes of a software application. Evaluation reveals that the system is accurate with prediction errors around 7% even for workloads involving simultaneous file system operations from multiple processes. The system creates virtually no power consumption overhead in the CPU and about 4% overhead in the RAM module. Results using I/O benchmarks demonstrate that a large portion of the energy usage (up to 100% in some cases) in modern disk drives can occur after the causative processes have already completed execution. Hence, results obtained using power meters or direct energy measurement systems based solely on a benchmark´s execution lifetime can drastically underestimate the benchmark application´s storage energy demands.