Implementation of compositional scheduling framework on virtualization

Abstract

Virtualization has been receiving increasing attention in embedded real-time systems. However, real-time systems, whose correctness depends on timing requirements, are not easily applicable to virtualization since virtualization mainly focuses on functional correctness. A hierarchical scheduling framework (HSF) provides a method of composing the complex timing requirements of real-time systems. There have been several works on the implementation of the HSF. Although the scheduling framework of virtualization directly corresponds to the HSF, they did not consider implementing the HSF on virtualization. In this paper, we implement a two-level HSF, where components use a periodic interface model using virtualization. We use an L4/Fiasco micro-kernel as a virtual machine monitor (VMM) and an L4Linux as a virtual machine (VM) and extend these to support real-time properties. The experimental results show that the HSF is suitable for the virtualization environment.