ProWATCh

Abstract

With the increase in process variations and diversity in workloads, it is imperative to holistically explore optimization techniques for power and temperature from the circuit layer right up to the compiler/ operating system (OS) layer. This article proposes one such holistic technique, called proactive workload aware temperature management framework for low-power chip multi-processors (ProWATCh). At the compiler level ProWATCh includes two techniques: (1) a novel compiler design for estimating the architectural parameters of a task at compile time; and (2) a model-based technique for dynamic estimation of architectural parameters at runtime. At the OS level ProWATCh integrates two techniques: (1) a workload- and temperature-aware process manager for dynamic distribution of tasks to different cores; and (2) a model predictive control-based task scheduler for generating the efficient sequence of task execution. At the circuit level ProWATCh implements either of two techniques: (1) a workload-aware voltage manager for dynamic supply and body bias voltage assignment for a given frequency in processors that support adaptive body bias (ABB); or (2) a workload-aware frequency governor for efficient assignment of upper and lower frequency bounds for frequency scaling in processors that do not support an ABB. Employing ProWATCh (with voltage manager) on an ABB-compatible 3D OpenSPARC architecture using MiBench benchmarks resulted in an average 18% ( 19ˆC ) reduction in peak temperature. Evaluating ProWATCh on an existing quad-core Intel Corei7 processor with frequency governor alone (as the processor does not support an ABB interface) resulted in 10% ( 8ˆC ) reduction in peak temperature when compared to what was obtained using the native Linux 3.0 completely fair scheduler (CFS). To study the effectiveness of the proposed framework across benchmark suites, ProWATCh was evaluated on a quad-core Intel Corei7 processor using CPU SPEC 2006 benchmarks which resulted in 7ˆC reduction in peak temperature as compared to the native Linux 3.0 CFS.