A novel hardware-accelerated real-time task scheduler based on robust earliest deadline algorithm

This paper presents novel design of a coprocessor that implements the existing task scheduling algorithm called Robust Earliest Deadline (RED). Thanks to the HW implementation, the scheduler operations are always completed in two clock cycles regardless of the number of tasks to be scheduled. Resource costs are evaluated by synthesis for Intel FPGA Cyclone V. Three different real-time task schedulers are compared: EDF-based scheduler suitable for hard real-time tasks only, GED-based scheduler suitable for soft real-time tasks only, and the proposed RED-based scheduler. The proposed scheduler handles deviations of task execution times better, achieves higher CPU utilization and can be used for scheduling of hard real-time, soft real-time and non-real-time tasks within one system, which was not possible with the former existing solutions.