I. Introduction
Multicores are more and more widely used in real-time systems to meet their rapidly increasing requirements in high performance and low power consumption. To fully utilize the computation power of multicore processors, software must be parallelized. The directed acyclic graph (DAG) task model is a widely used representation to model parallel real-time tasks. Recently, real-time scheduling and analysis of DAG tasks has gained rapidly increasing interests [1]–[15]. In this article, we focus on the schedulability analysis problem of DAG tasks under global EDF (GEDF) scheduling.