Real-time scheduling with MLFQ-RT multilevel feedback queue with starvation mitigation

Abstract

Process scheduling for real-time processes is a critical function of real-time operating systems, which are required to guarantee soft and hard deadlines for completing real-time processes. The behavior of Multi-Level Feedback Queue (MLFQ) scheduling mechanisms intrinsically support a scheduling that favors short CPU bursts to the complete exclusion of all other processes in the ready queues. This MLFQ feature can be extended to support meeting both hard and soft real-time process deadlines. This research proposes a new derivative of MLFQ for real-time scheduling call MLFQ-Real-Time (MLFQ-RT) investigated through simulation. The MLFQ-RT real-time extension builds upon research solving a known weakness of MLFQ scheduling: a vulnerability to starvation of processes in the lowest priority queue, so that the operating system is unable to guarantee that all processes will make progress. Simulation research demonstrates that MLFQ-RT can support hard and soft real-time process scheduling while simultaneously mitigating starvation in low priority queues.