CSR--EHS--Reconciling Operating System and Hardware Thermal Control

该项目开发具有动态热管理(DTM-也称为热节流)的系统的实时控制。DTM使冷却解决方案的设计低于最坏情况，随着功率密度的成倍增加和外形尺寸的缩小，这种方法变得越来越必要。在运行时，如果散热持续超过冷却解决方案的能力，并且芯片上的温度接近危险水平，则DTM会将处理器置于某种形式的低功耗模式，从而使温度回落到安全水平。问题是，当前系统中的DTM通常在热应力迫在眉睫时由硬件自主参与，没有任何警告。这与实时调度不兼容。为了协调运行时热管理和实时控制，本研究正在开发新的调度算法和必要的软件和硬件支持。这包括快速估计工作负载的未来热负载、估计DTM的可能性和调度影响，以及允许操作系统选择最方便的时间来使用DTM的新方法。在具有真实工作负载的真实试验台上对所提出的技术进行了评估。

This project develops real-time control of systems with dynamic thermal management (DTM-also called thermal throttling). DTM allows the cooling solution to be designed for less than the worst case, an approach that is becoming necessary with exponentially increasing power densities and shrinking form factors. At runtime, if heat dissipation exceeds the cooling solution's capacity for a sustained period of time and on-chip temperatures approach dangerous levels, DTM places the processor in some form of low-power mode that allows temperatures to fall back to a safe level. The problem is that DTM in current systems is typically engaged autonomously by the hardware when thermal stress is imminent, without any warning. This is incompatible with real-time scheduling. To reconcile runtime thermal management with real-time control, new scheduling algorithms and requisite software and hardware support are being developed in this research. This includes fast estimation of a workload's future thermal load, estimation of the likelihood and scheduling impact of DTM, and new methods that allow the operating system to choose the most convenient time to engage DTM. The proposed techniques are evaluated on a real testbed with realistic workloads.