Application-Level Energy Awareness for OpenMP

Power, and consequently energy, has recently attained firstclass system resource status, on par with conventional metrics such as CPU time. To reduce energy consumption, many hardwareand OSlevel solutions have been investigated. However, application-level information which can provide the system with valuable insights unattainable otherwise was only considered in a handful of cases. We introduce OpenMPE, an extension to OpenMP designed for power management. OpenMP is the de-facto standard for programming parallel shared memory systems, but does not yet provide any support for power control. Our extension exposes (i) per-region multi-objective optimization hints and (ii) application-level adaptation parameters, in order to create energysaving opportunities for the whole system stack. We have implemented OpenMPE support in a compiler and runtime system, and empirically evaluated its performance on two architectures, mobile and desktop. Our results demonstrate the effectiveness of OpenMPE with geometric mean energy savings across 9 use cases of 15% while maintaining full quality of service.