The combination of a real-time executive and off-the-shelf time-sharing operating systems has the potential of providing both predictability and the comfort of a large application base. Isolation between the components is required to protect the real-time subsystem from a significant class of faults in the (ever-growing) time-sharing operating systems but also to protect real-time applications from each other. Recent commodity computer hardware significantly improved the ability of these machines to support faithful virtualization. Virtual machines provide the strong isolation required for security reasons. But questions regarding the temporal isolation remain open. In this paper we analyze how and to which degree recent x86 virtualization extensions influence the interrupt-response times of a real-time operating system hosting virtual machines.
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