Scheduling of mixed-criticality applications on resource-sharing multicore systems

Abstract

A common trend in real-time safety-critical embedded systems is to integrate multiple applications on a single platform. Such systems are known as mixed-criticality (MC) systems as the applications are usually characterized by different criticality levels (CLs). Nowadays, multicore platforms are promoted due to cost and performance benefits. However, certification of multicore MC systems is challenging because concurrently executed applications with different CLs may block each other when accessing shared platform resources. Most of the existing research on multicore MC scheduling ignores the effects of resource sharing on the execution times of applications. This paper proposes a MC scheduling strategy which explicitly accounts for these effects. Applications are executed by a flexible time-triggered criticality-monotonic scheduling scheme. Schedulers on different cores are dynamically synchronized such that only a statically known subset of applications of the same CL can interfere on shared resources, e. g.,memories, buses. Therefore, the timing effects of resource sharing are bounded and we quantify them at design time. We combine this scheduling strategy with a mapping optimization technique for achieving better resource utilization. The efficiency of the approach is demonstrated through extensive simulations as well as comparisons with traditional temporal partitioning and state-of-the-art scheduling algorithms. It is also validated on a real-world avionics system.