On the complexity of optimal priority assignment for periodic tasks upon identical processors
نویسنده
چکیده
In this paper we study global fixed-priority scheduling of periodic task systems upon identical multiprocessor platforms. Based on existing feasibility tests for periodic task systems upon identical multiprocessor platforms, we show (using a dummy priority assignment algorithm) that optimal priority assignment for these systems exists. Then we provide an algorithm based on RMUS[m/(3m−2)] that has lower complexity. Finally, we conjuncture that, contrary to the general opinion, (pseudo-) polynomial optimal priority assignment algorithms for periodic task systems upon identical processors might exist.
منابع مشابه
Optimal Utilization Bounds for the Fixed-priority Scheduling of Periodic Task
In fixed-priority scheduling the priority of a job, once assigned, may not change. A new fixed-priority algorthm for scheduling systems of periodic tasks upon identical multiprocessors is proposed. This algorithm has an achievable utilization of (m + 1)/2 upon m unit-capacity processors. It is proven that this algorithm is optimal from the perspective of achievable utilization, in the sense tha...
متن کاملOptimal Priority Assignment for Aperiodic Tasks with Firm Deadlines in Fixed Priority Pre-Emptive Systems
An optimal priority assignment policy is presented for independent aperiodic tasks with arbitrary ready times and firm deadlines, scheduled on a uniprocessor along with a set of hard periodic/sporadic tasks. The latter tasks are assumed to have been assigned unique fixed priorities according to some arbitrary policy and guaranteed, via off-line feasibility analysis, to meet their deadlines. In ...
متن کاملScheduling Distributed Real-Time Tasks in the DGMF Model
Analytical results on the real-time scheduling of multiprocessor systems have focussed on partitioning and distributing the task set for scheduling on identical single processors, with the assumption that all of a task can be executed on any of a pool of identical processors. A distributed system is a set of nodes networked together. Each node may have a different type of processor and performs...
متن کاملTask Partitioning and Priority Assignment for Hard Real-time Distributed Systems
The partitioning of fixed-priority hard real-time tasks and messages in a distributed system is a well known NP-hard problem. Therefore, there are no methods that provide an optimal solution in polynomial time. In this paper, we propose the Distributed using Optimal Priority Assignment (DOPA) heuristic, which simultaneously solves the problem of assigning task to processors and assigning priori...
متن کاملOptimal Scheduling of Periodic Tasks on Multiple Identical Processors
We consider the problem of scheduling m periodic tasks on n; n < m; identical processors. Our main contribution is to show that the condition n, where is the total density of the task set, is a suucient condition for scheduling the m tasks such that no deadlines are ever missed. We start with a novel representation of the periodic task scheduling problem as a maximum network ow problem. The str...
متن کامل