Abstract: Since the self-structure of the DAG(directed acyclic graph)task is not considered， the schedulability analysis of the DAG parallel task model based on G-EDF(global earliest deadline first)is very pessimistic. The response time analysis of the DAG task set under the G-EDF scheduling strategy in multiprocessor systems was studied in this paper. First， a more accurate carry-in workload estimation method was proposed for the execution of the carry-in task instance. Then a method for estimating the problem window workload of completion time was put forward based on the carry-in workload estimation method. Based on the two proposed methods， this paper proposed a response time analyzing method to derive a response time upper bound of each task. The experiments show that the proposed method outperforms the state-of-the-art method by at least 15% and at most 25%.

Key words: embedded real-time systems, multiprocessors, parallel tasks model, global scheduling, response time analysis