Holistic analysis of asynchronous real-time transactions with earliest deadline scheduling

In this paper, we study the problem of reducing the energy consumption for hard real-time systems scheduled according to either fixed-priority (FP) or earliest-deadline-first (EDF) scheme. To balance the static and dynamic energy consumptions, the concept of critical speed was proposed in previous research. Moreover, when combined with the processor idle/shutdown state, the critical speed was widely used as the lower bound for voltage scaling in literature. In this paper, we show that this strategy might not always be more energy efficient than the traditional DVS strategy and there exists a dynamic tradeoff between these two strategies depending on the job’s work-demand to be finished within certain intervals. To effectively address this issue, we propose a unified approach that combines these two strategies to achieve better overall energy saving performance. Our approach determines the energy-efficient speeds for real-time jobs in their corresponding feasible intervals based on the threshold work-demand analysis. Our experimental results demonstrate that the proposed techniques significantly outperform previous approaches in the overall energy saving performance.

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Exploitation of the EDF Scheduling in the Wireless Sensors Networks

Advanced Instrument Engineering ◽

10.4018/978-1-4666-4165-5.ch007 ◽

2013 ◽

pp. 87-100

Author(s):

Rym Chéour ◽

Sébastien Bilavarn ◽

Mohamed Abid

Keyword(s):

Wireless Sensor Networks ◽

Sensor Networks ◽

Real Time ◽

Management Policy ◽

Wireless Sensor ◽

Periodic Tasks ◽

Real Time Scheduling ◽

Scheduling Policy ◽

Time Scheduling ◽

Earliest Deadline

Today, due to recent advances in wireless technology, new products using wireless sensor networks are being employed. However, despite the excitement surrounding wireless sensor networks, it is not immune to the problem of energy consumption. To overcome this deficiency and enhance the real time aspect, a growing interest lies in the implementation of an “Earliest Deadline First” (EDF) scheduler. Thus, in this paper, the authors establish a management policy of periodic tasks that is preemptive, multiprocessor, and dynamic. The authors implement a real-time scheduling policy as a part of a user-level threads package under the Linux operating system as Linux does not support EDF. Furthermore, this paper describes the technique of the EDF scheduler and how it can yield to significant power savings.

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ACO Based Dynamic Scheduling Algorithm for Real-Time Multiprocessor Systems

Applications and Developments in Grid, Cloud, and High Performance Computing ◽

10.4018/978-1-4666-2065-0.ch006 ◽

2013 ◽

pp. 85-96

Author(s):

Apurva Shah ◽

Ketan Kotecha

Keyword(s):

Real Time ◽

Computational Models ◽

Dynamic Scheduling ◽

Scheduling Algorithm ◽

Earliest Deadline First ◽

Multiprocessor Systems ◽

Individual Agent ◽

Collective Foraging ◽

Time Systems ◽

Earliest Deadline

The Ant Colony Optimization (ACO) algorithms are computational models inspired by the collective foraging behavior of ants. The ACO algorithms provide inherent parallelism, which is very useful in multiprocessor environments. They provide balance between exploration and exploitation along with robustness and simplicity of individual agent. In this paper, ACO based dynamic scheduling algorithm for homogeneous multiprocessor real-time systems is proposed. The results obtained during simulation are measured in terms of Success Ratio (SR) and Effective CPU Utilization (ECU) and compared with the results of Earliest Deadline First (EDF) algorithm in the same environment. It has been observed that the proposed algorithm is very efficient in underloaded conditions and it performs very well during overloaded conditions also. Moreover, the proposed algorithm can schedule some typical instances successfully which are not possible to schedule using EDF algorithm.

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A Real-Time Message Scheduling Scheme Based on Optimal Earliest Deadline First Policy for Dual Channel Wireless Networks

Embedded and Ubiquitous Computing - Lecture Notes in Computer Science ◽

10.1007/11802167_28 ◽

2006 ◽

pp. 264-273 ◽

Cited By ~ 3

Author(s):

Junghoon Lee ◽

Mikyung Kang ◽

Gyung-Leen Park ◽

Ikchan Kim ◽

Cheolmin Kim ◽

...

Keyword(s):

Wireless Networks ◽

Real Time ◽

Earliest Deadline First ◽

Scheduling Scheme ◽

Dual Channel ◽

Message Scheduling ◽

Earliest Deadline

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Limited Non-Preemptive EDF Scheduling for a Real-Time System with Symmetry Multiprocessors

Symmetry ◽

10.3390/sym12010172 ◽

2020 ◽

Vol 12 (1) ◽

pp. 172 ◽

Cited By ~ 1

Author(s):

Hoyoun Lee ◽

Jinkyu Lee

Keyword(s):

Real Time ◽

Scheduling Algorithm ◽

Schedulability Analysis ◽

Timing Constraints ◽

Limited Information ◽

Time System ◽

Real Time System ◽

System A ◽

The Future ◽

Earliest Deadline

In a real-time system, a series of jobs invoked by each task should finish its execution before its deadline, and EDF (Earliest Deadline First) is one of the most popular scheduling algorithms to meet such timing constraints of a set of given tasks. However, EDF is known to be ineffective in meeting timing constraints for non-preemptive tasks (which disallow any preemption) when the system does not know the future job release patterns of the tasks. In this paper, we develop a scheduling algorithm for a real-time system with a symmetry multiprocessor platform, which requires only limited information about the future job release patterns of a set of non-preemptive tasks, called LCEDF. We then derive its schedulability analysis that provides timing guarantees of the non-preemptive task set on a symmetry multiprocessor platform. Via simulations, we demonstrate the proposed schedulability analysis for LCEDF significantly improves the schedulability performance in meeting timing constraints of a set of non-preemptive tasks up to 20.16%, compared to vanilla non-preemptive EDF.

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