Designing Efficient Algorithms for the Eventually Perfect Failure Detector Class

This paper focuses on the design of unreliable failure detectors of the Eventually Perfect class (3P) in crash-prone partially synchronous systems. We adopt a monitoring mechanism based on heartbeats over a logical ring arrangement of processes as the common design feature. This provides good communication efficiency, a performance parameter which refers to the number of links that carry messages forever. We follow two different approaches that result in two families of failure detectors: a nearly communication-efficient family, which uses n + C links forever, being C the number of correct processes out of the n processes in the system, and a communicationefficient family, which uses only n links forever. Besides communication efficiency, we evaluate the algorithms in terms of QoS parameters, which include the capability of the failure detector to provide right answers as well as its reaction time.