Improving Real-Time Performance of a Virtual Machine Monitor Based System

This paper describes our approach to enable Gandalf VMM (Virtual Machine Monitor) to be interruptible. Although Gandalf is shown to be a lightweight VMM, the detailed performance analysis using PMC (Performance Monitoring Counters) showed Gandalf executes with interrupts disabled for a rather long duration of time. By making Gandalf interruptible, we are able to make VMM based systems more suitable for embedded and ubiquitous systems. We analyzed the requirements to make Gandalf interruptible, designed and implemented the mechanisms to realize it. The experimental results shows that making Gandalf interruptible significantly reduces a duration of execution time with interrupts disabled while it does not impact the performance.