Task Migration Policy for Thermal-Aware Dynamic Performance Optimization in Many-Core Systems

Abstract

The steady downsizing of semiconductor technology nodes in recent years has led to a rapid increase in the density of power consumption on chips which, in turn, renders temperature a major issue for many-core systems, adversely affecting their performance, reliability, leakage, cost, etc. In this context, task migration is a powerful technique that is widely used for controlling the temperature profile of many-core systems under dynamic workloads with the goal to improve their performance, utilization, reliability, etc. In this paper, we present a task migration policy for thermal-aware performance optimization in heterogeneous many-core systems. The proposed policy is developed based on an analytical and thermally safe power-budgeting scheme and uses Dynamic Voltage and Frequency Scaling (DVFS) for power and thermal management of the system. Our migration policy aims at maximizing the system's performance and, at the same time, proactively enforcing thermal safety using DVFS. To that end, it iteratively adapts the distribution of active cores in the system (through proper migration decisions) to maximize the thermally safe power budget of active cores and, thereby, enable them to operate on higher frequencies without violating their safe thermal threshold. Experimental results demonstrate that the proposed policy offers 2times higher performance gain in comparison to existing approaches which aim at greedily reducing the average, variance, or gradient of temperature as an indirect means to enhance performance.