A case study of hybrid WCET analysis for Xen virtulization

Virtualization technologies have become a new trend in embedded real-time systems. However, due to the extra layers introduced by virtualization, the worst-case execution time (WCET) analysis for the real-time tasks becomes more complicated as compared to systems that without virtualization. In this paper, we study the timing characteristics of virtualization system and propose a hybrid timing analysis method for the para-virtualization X86 platform with Xen [17], which provides a simple and fast WCET analysis solution to the target system. Our experiments indicate that the proposed hybrid timing analysis method can provide safe upperbound for real-time programs running on Xen [17], with an average of 17% overestimation as compared to the worst-case observed execution time.