Adaptive Monitoring in Microkernel OSs

The microkernel architecture has been investigated by both industries and the academia for the development of dependable Operating Systems (OSs). This work copes with a relevant issue for this architecture, namely unresponsive components because of deadlocks and infinite loops. In particular, a monitor sends heartbeat messages to a component that should reply within a timeout. The timeout choice is tricky, since it should be dynamically adapted to the load conditions of the system. Therefore, our approach is based on an adaptive heartbeat mechanism, in which the timeout is estimated from past response times. We implement and compare three estimation algorithms for the choice of the timeout in the context of the Minix 3 OS. From the analysis we derive useful guidelines for choosing the best algorithm with respect to system requirements.