Abstract-Mixed-criticality real-time systems, where tasks may be associated with different criticality and assurance levels, have attracted much attention in the recent past. In this paper, we consider partitioning-based multiprocessor scheduling of mixedcriticality real-time task sets. Guaranteeing feasibility in this setting is shown to be NP-Hard. With a focus on fixed-priority preemptive scheduling on each processor, we identify the two main aspects of the problem, namely the task allocation and priority assignment dimensions. For the task allocation dimension, we propose and compare bin-packing-inspired heuristics, based on offline task ordering according to utilization and criticality. For the priority assignment dimension, we compare the wellknown Rate Monotonic priority assignment policy with Audsley's priority assignment algorithm. Through simulations, we also assess and discuss the relative importance of these two primary dimensions on the overall mixed-criticality feasibility problem for multiprocessor platforms.

There has been a growing interest in recent years in mixed-criticality real-time systems in which tasks are attributed different levels of criticality based on the degree to which their deadlines must be assured. While most of the initial efforts on mixed-criticality systems targeted single-processor systems, the research community has recently started to investigate multiprocessor mixed-criticality real-time systems. In this paper we investigate how global, fixed-priority algorithms can be applied in the context of multiprocessor mixed-criticality systems. We identify the two key dimensions of the problem -priority assignment and schedulability testing, and consider candidate algorithms for each dimension. We also propose a new and simple priority assignment policy called CPRatio that considers both task criticality and timing constraints to improve the schedulability of mixed-criticality task sets. We experimentally evaluate the performance of priority assignment strategies and schedulability tests in the global multiprocessor mixed-criticality scheduling context. Keywords: mixed-criticality; real-time scheduling; global scheduling; fixed-priority scheduling; multiprocessor scheduling; schedulability tests.