Exploring the design space of multiprocessor synchronization protocols for real-time systems

The goal of this paper is to explore the design space of protocols for multiprocessor systems with static priority and partitioned scheduling. The design space is defined by a set of characteristics that can vary from one protocol to another. This exploration presents new protocols with different characteristics from existing ones. These new protocols are considered variations of the Multiprocessor Priority Ceiling Protocol (MPCP), but they can also be seen as variations of the Flexible Multiprocessor Locking Protocol (FMLP), since they include features common to both protocols. Schedulability tests are provided for these new variations and they are compared with the original versions of MPCP and FMLP. Such comparisons include an empirical comparison of schedulability and an overhead evaluation of a real implementation. Such comparisons show that these new variations are actually competitive in relation to the existing protocols.