Real-time tasks and voltage/frequency controller collaboration on low power energy operational systems

Embedded systems have evolved significantly in recent years, mainly due to advances in technology, cost reduction of electronic equipment, and the popularization of mobile devices. Many of these systems require energy resources from battery to maintain the operation of their various components. However, to increase the autonomy of these devices, several techniques and methodologies have been implemented to better manage energy consumption of the system as a whole. This requirement has contributed to the rise of various lines of research, including the area of real-time systems, in which the complicating factor is not only reducing energy consumption but also respecting the time constraints of all tasks running on the system. Thus, this work aims to minimize energy consumption by using intra-task dynamic voltage and frequency scaling (DVFS) technique, through a collaborative approach between real-time applications and the operating system. Therefore, both can work together, within the kernel of the system, to reduce the overhead of the processor context switches, mainly after preemptions. The experimental results, using C-Benchmarks, showed that it is possible to decrease about 6% of processor power consumption even performing all tasks in the worst case.