Scheduling slack time in fixed priority pre-emptive systems
نویسندگان
چکیده
This report addresses the problem of jointly scheduling tasks with both hard and soft time constraints. We present new analysis which builds upon previous research into slack stealing algorithms. Our analysis determines the maximum processing time which may be stolen from hard deadline periodic or sporadic tasks, without jeopardising their timing constraints. It extends to tasks with characteristics such as synchronisation, release jitter and stochastic execution times, as well as forming the basis for research into optimal and approximate slack stealing algorithms.
منابع مشابه
A Fast Slack Stealing method for embedded Real-Time Systems
In this paper we present a low-cost Slack-Stealing method, named Fast Slack, to be employed in a Fixed Priority scheduling mechanism. The slack obtained is intended to improve the execution of non-critical tasks without jeopardizing the schedulability of the critical ones. The method is compared with the most important one in the realtime theory. We show that the complexity of this method is su...
متن کاملGlobal Fixed Priority Scheduling with Deferred Pre-emption Revisited
This paper introduces schedulability analysis for global fixed priority scheduling with deferred pre-emption (gFPDS) for homogeneous multiprocessor systems. gFPDS is a superset of global fixed priority pre-emptive scheduling (gFPPS) and global fixed priority non-pre-emptive scheduling (gFPNS). We show how schedulability can be improved via appropriate choice of priority assignment and final non...
متن کاملGlobal Rate-Monotonic Scheduling with Priority Promotion
In this paper, we consider a multicore real-time scheduling algorithm incorporating benefits of both fixed-priority and dynamic-priority disciplines. Specifically, the algorithm first assigns globally-effective priorities to real-time tasks statically, based on the well-known Rate-Monotonic scheduling policy. It may however change the task priorities at runtime, only when the tasks reach the ze...
متن کاملApproximate Slack Stealing Algorithms for Fixed Priority Pre-emptive Systems
Recent research into the problem of jointly scheduling tasks with both hard and soft time constraints has focused on the development of optimal slack stealing algorithms. Theoretically, these optimal algorithms offer significant performance improvements over previous bandwidth preserving algorithms such as the Sporadic Server or Extended Priority Exchange algorithm. However, there are problems ...
متن کاملOn Optimal Priority Assignment for Response Time Analysis of Global Fixed Priority Pre-emptive Scheduling in Multiprocessor Hard Real-Time Systems
This paper investigates the problem of optimal priority assignment in multiprocessor real-time systems using global fixed task-priority pre-emptive scheduling. Previous work in this area showed that arguably the most effective pseudo-polynomial schedulability tests for global fixed priority pre-emptive scheduling, based on response time analysis, are not compatible with Audsley’s Optimal Priori...
متن کامل