Quantum support for mul-tiprocessor Pfair scheduling in Linux

This paper discusses several modifications to the Linux operating system in order to support aligned, staggered, and desynchronized quanta across multiple processors, where a quantum is a unit of processor allocation. We also evaluate one approach for supporting aligned quanta. These types of quanta are required for global multipro- cessor real-time scheduling algorithms such as PD2 (a Pfair algorithm). Additionally, we consider the issue of increasing the frequency of timer interrupts to allow for the smallest quantum possible, and discuss impediments to higher timer interrupt frequencies. Smaller quanta are important, as they can increase the efficiency of quantum-based scheduling algorithms; however, they are more sensitive to quantum alignment error.