CPU temperature aware scheduler a study on incorporating temperature data for CPU scheduling decisions

Power management in embedded devices is of paramount importance. Heat generated by CPUs is one of the important factors contributing to the battery life of the handheld devices. In Linux kernel, the problem of heat generation by CPUs is tackled by the thermal subsystem. The thermal subsystem limits the heat generation due to CPUs by limiting the maximum frequency of a CPU. This is made possible by a HW specific driver to control the operating points of CPU. This paper presents a novel approach to tackle the heat generation in CPUs. In this paper a temperature aware scheduler is proposed where temperature of CPU core is considered as an important parameter in task placement decisions. The method intends to lower the heat generated by CPUs and lower the number of thermal mitigations done by the thermal subsystem. The test results performed on an embedded device showed a trend of significantly delayed thermal mitigations and better performance in general compared to stock kernel.