Implications of the amd-pstate Driver for Frequency Scaling in Energy-Efficient Task Scheduling

Discrete processor frequencies add complexity to task scheduling problems that take frequency scaling into account as a means to control and predict task runtimes and system power consumption. Moreover, if the set of available frequencies is small—as has traditionally been the case with AMD’s x86 processors—energy efficiency is seriously threatened. The amd-pstate scaling driver promises continuous frequency scaling on recent AMD systems from the Zen 2 microarchitecture onward, which could relieve these issues. We present an empirical investigation into whether the claimed capabilities indeed exist and are accessible to the user, and we discuss the implications for energy-efficient task scheduling.