Research on multi-core scheduling method for Sporadic task by line tree mode

Abstract

At present, most of the scheduling models for real-time periodic tasks are established based on independent fixed periodic tasks and few by considering the task model with period allowed to change and the processor model in the scheduling process. In this paper, a task model and processor model based on line tree(LT) for sporadic real-time periodic tasks are designed, and a transformation algorithm from task line tree(TLT) model to processor line tree(PLT) model is proposed. The algorithm takes the least common multiple of all real-time periodic tasks as the benchmark of layer number, and based on the complete job replacement rule, the minimum common multiple of all real-time periodic tasks is used as the reference of layer number. In order to achieve the optimal multiprocessor scheduling result, the method of replacing the empty node of non-migrating job with the node of migrating job and the condition of allowing job to publish tasks ahead of time with variable cycle are used. Experimental results show that comparing with PEDF, GEDF and RMFF, the present method not only has higher core utilization and lower time loss rate, but also reduces the number of context switching and migration.