Regulating CPU Temperature With Thermal-Aware Scheduling Using a Reduced Order Learning Thermal Model

TL;DR

This paper introduces POD-TAS, a thermal-aware scheduling algorithm for multi-core CPUs that uses a reduced order thermal model to effectively manage heat, outperforming existing methods in reducing peak temperatures and thermal variance.

Contribution

The paper presents a novel thermal-aware scheduling algorithm, POD-TAS, based on a reduced order thermal model, and demonstrates its superior thermal management performance over existing algorithms.

Findings

POD-TAS reduces peak thermal variance by 53.0% with 4 benchmarks.

POD-TAS decreases peak chip temperature by 29.01%.

Compared to RT-TAS, POD-TAS lowers peak spatial variance by 29.57%.

Abstract

Modern real-time systems utilize considerable amounts of power while executing computation-intensive tasks. The execution of these tasks leads to significant power dissipation and heating of the device. It therefore results in severe thermal issues like temperature escalation, high thermal gradients, and excessive hot spot formation, which may result in degrading chip performance, accelerating device aging, and premature failure. Thermal-Aware Scheduling (TAS) enables optimization of thermal dissipation to maintain a safe thermal state. In this work, we implement a new TAS algorithm, POD-TAS, which manages the thermal behavior of a multi-core CPU based on a defined set of states and their transitions. We compare the performances of a dynamic RC thermal circuit simulator (HotSpot) and a reduced order Proper Orthogonal Decomposition (POD)-based thermal model and we select the latter for use in our POD-TAS algorithm. We implement a novel simulation-based evaluation methodology to compare TAS algorithms. This methodology is used to evaluate the performance of the proposed POD-TAS algorithm. Additionally, we compare the performance of a state of the art TAS algorithm, RT-TAS, to our proposed POD-TAS algorithm. Furthermore, we utilize the COMBS benchmark suite to provide CPU workloads for task scheduling. Our experimental results on a multi-core processor using a set of 4 benchmarks demonstrate that the proposed POD-TAS method can improve thermal performance by decreasing the peak thermal variance by 53.0% and the peak chip temperature of 29.01%. Using a set of 8 benchmarks, the comparison of the two algorithms shows a decrease of 29.57% in the peak spatial variance of the chip temperature and 26.26% in the peak chip temperature. We also identify several potential future research directions.