Response Time Analysis of Hierarchical Scheduling: the Synchronized Deferrable Servers Approach

Hierarchical scheduling allows the use of different schedulers and provides temporal isolation for different applications on a single hardware platform. We propose a hierarchical scheduling interface called synchronized deferrable servers. In addition to the common advantages of hierarchical scheduling, synchronized deferrable servers can combine partitioned and global multiprocessor scheduling in one system, and increase the schedulable system utilization. Response time analysis of tasks executed by these servers is presented and evaluated through simulation. We show that evenly allocating bandwidth across cores is “better” than other allocation schemes in terms of a task set’s schedulability. In addition, under hierarchical scheduling, the threshold between lightweight and heavyweight tasks may be different from what they are under dedicated scheduling