Current Results on EDZL Scheduling for Multiprocessor Real-Time Systems
Hsin‐Wen Wei, Yi-Hsiung Chao, Shun‐Shii Lin, Kwei-Jay Lin, Wei‐Kuan Shih · 2007
Many optimal uniprocessor schedulers, such as earliest deadline first (EDF) and rate monotonic (RM), do not have a good schedulability bound on multiprocessor systems. In this paper, we study an on-line algorithm earliest deadline first until Zero laxity (EDZL) for multiprocessor systems. A set of tasks scheduled by EDZL is scheduled using EDF until a job experiences a zero laxity. To avoid the job from missing its deadline, the priority of the job is immediately promoted to the highest priority. We derive the schedulability bound of 3/2+\umax-1/2\ for two-processor systems, where umaxis the maximum utilization of an individual task in the given task set. We also discuss the best known upper bound and lower bound on EDZL schedulability conditions.