Energy-aware real-time scheduling in the linux kernel

The recent changes made in the Linux kernel aim at achieving better energy efficiency through a tighter integration between the CPU scheduler and the frequency-scaling subsystem. However, in the current implementation, the frequency scaling mechanism is used only when there are no real-time tasks in execution. This paper shows how the deadline scheduler and the cpufreq subsystem can be extended to relax this constraint and implement an energy-aware real-time scheduling algorithm. In particular, we describe the design issues encountered when implementing the GRUB-PA algorithm on a real operating system like Linux. A set of experimental results on a multi-core ARM platform validate the effectiveness of the proposed implementation.