A Universal Method for Task Allocation on FP-FPS Multiprocessor Systems with Spin Locks

Many complex real-time systems, such as increasingly automated vehicles and 5G wireless base stations, contain a large amount of shared resources that must be accessed in a mutually exclusive fashion. This leads to significant contention especially when resources are shared across processors. To reduce the contention, various resource-aware task allocation methods have been developed to localize the shared resources. Unfortunately, these existing methods either are tailored for specific scheduling and analysis approaches, or introduce runtime overhead that undermines their applicability. In this paper, we present a task allocation method for a mainstream type of real-time systems in practice: FP-FPS (fully-partitioned fixed-priority scheduling) multiprocessor systems with spin locks managing shared resources. Instead of relying on timing bounds as guidance, we utilize a model to approximate the degree of resource contention between tasks. The model is decoupled from priority assignment algorithms, resource sharing protocols and schedulability tests. Hence, our task allocation method can be applied without detailed knowledge of the underlying system, which is particularly useful during the initial design phase of the system. More detailed information about the system in the later phases of design will push up the approximation accuracy and further enhance the performance. Experimental results show that the proposed method outperforms the state-of-the-art by 13.6% on average (up to 24.2%) in system schedulability with a much less (57x on average) computation cost and negligible runtime overhead.