Resource Hold Times under Multiprocessor Static-Priority Global Scheduling

Recently there has been a lot of interest in coexisting of multiple independently-developed real-time applications on a shared open platform. On the other hand, emerging of multi-core platforms and the performance and possibilities they offer has attracted a lot of attention in multiprocessor real-time analysis, protocols and techniques. Co-executing independently-developed real-time applications on a shared multiprocessor system, where each application executes on a dedicated sub set of processors, requires to overcome the problem of handling mutually exclusive shared resources among those applications. To handle resource sharing, it is important to determine the Resource Hold Time (RHT), i.e., the maximum duration of time that an application locks a shared resource. In this paper, we study resource hold times under multiprocessor static-priority global scheduling. We present how to compute RHT´s for each resource in an application. We also show how to decrease the RHT´s without compromising the schedulability of the application. We show that decreasing all RHT´s for all shared resources is a multiobjective optimization problem and there can exist multiple Pareto-optimal solutions.