Solving the group priority inversion problem in a timed asynchronous system

• Published in: IEEE transactions on computers 2002-08, Vol.51 (8), p.900-915
• Main Authors: Yun Wang, Anceaume, E., Brasileiro, F., Greve, F., Hurfin, M.
• Format: Article
• Language: English
• Subjects: Computer Society; Delay; Detectors; Fault tolerant systems; Mechanical factors; Predictive models; Processor scheduling; Protocols; Real time systems; Synchronization
• ISSN: 0018-9340; 1557-9956
• DOI: 10.1109/TC.2002.1024738

Considers the priority inversion problem in an actively replicated system. Priority inversion was originally defined in the context of nonreplicated systems. Therefore, we first introduce the concept of group priority inversion, which extends the concept of (local) priority inversion to the context of a group of processors that perform an actively replicated processing. We then present the properties of a request scheduling protocol to enforce a total ordering for the processing of requests while avoiding group priority inversions. These properties have been implemented in a protocol that relies on a timed asynchronous system model equipped with a failure detector of the class /spl diams/S. The proposed solution allows us to replicate a critical server while ensuring that the processing of all the incoming requests is consistent (mechanisms for solving the atomic broadcast problem) and predictable (mechanisms for solving the group priority inversion problem). Thus, the described request scheduling protocol is a key component which can be used to develop fault-tolerant real-time applications in a timed asynchronous system.