Enabling Hardware Performance Counters for Microkernel-Based Virtualization on Embedded Systems

Virtualization techniques continue to evolve at rapid speed and have now come to find its application in embedded and mobile computing devices. Virtualization improves the utilization of system resources effectively and also enhances security by providing isolated environments to run untrusted applications. There are various approaches to virtualization of embedded systems, from among them, we have chosen microkernel-based virtualization for our analysis due to its low memory requirements and advantages in terms of security. The microkernel selected for our work is the L4/Fiasco microkernel. Most of the modern CPUs consist of Performance Monitoring Unit (PMUs), which have a set of hardware counters that can be configured to monitor events. These hardware performance counters in the PMU block is not accessible from a microkernel-based virtualization environment. Access to PMU from a virtual environment would facilitate profiling with better accuracy and reduced overheads. To get this realized we propose a method to access the hardware performance counters from a microkernel-based virtualization environment. We have used this implementation to analyze the performance of applications in a microkernel-based virtual environment and to compare its performance in a non-virtual environment.