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

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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An Algorithm to Reduce the Time Complexity of Earliest Deadline First Scheduling Algorithm in Real-Time System

International Journal of Advanced Computer Science and Applications ◽

10.14569/ijacsa.2011.020207 ◽

2011 ◽

Vol 2 (2) ◽

Cited By ~ 6

Author(s):

Jagbeer Singh ◽

Bichitrananda Patra ◽

Satyendra Prasad

Keyword(s):

Real Time ◽

Time Complexity ◽

Scheduling Algorithm ◽

Earliest Deadline First ◽

Time System ◽

Real Time System ◽

Earliest Deadline

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Energy Efficient Scheduling Algorithm for Soft Real Time System with High Deadline Meeting Rate on Overload

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.699.840 ◽

2014 ◽

Vol 699 ◽

pp. 840-845

Author(s):

Zahereel Ishwar Abdul Khalib ◽

R. Badlishah Ahmad ◽

Ong Bi Lynn

Keyword(s):

Power Consumption ◽

Real Time ◽

Scheduling Algorithm ◽

Simulation Method ◽

Process Scheduling ◽

Time System ◽

Real Time System ◽

System Load ◽

Percent Improvement ◽

Earliest Deadline

The fact that earliest deadline first (EDF) scheduling algorithm behaves unpredictably during overload is an old and existing issue in the field of real time system. In this paper, a new software process scheduling algorithm for soft real time applications is presented. The algorithm is formulated by means of logical reasoning and excessive simulation method. This method is adopted due to the fact that the problem of scheduling a set of periodic task on single processor using non-preemptive scheme is NP-hard in the strong sense. The new algorithm, with inherently less computational complexity is found to improve in power consumption by almost 50 percent at the peak of practical overload which is at 150 percent of system load. At the same system load, the new algorithm also gives a minimum of 16 percent improvement in deadline meeting rate (DMTR) as compared to EDF. Design and formulation of the new algorithm along with graphical results of the power consumption level and the level of the deadline meeting rate of both algorithms will be presented and discuss in detail.

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Performance Evaluation of New Joint EDF-RM Scheduling Algorithm for Real Time Distributed System

Journal of Engineering ◽

10.1155/2014/485361 ◽

2014 ◽

Vol 2014 ◽

pp. 1-13 ◽

Cited By ~ 2

Author(s):

Rashmi Sharma ◽

Nitin

Keyword(s):

Real Time ◽

Distributed System ◽

Scheduling Algorithm ◽

Earliest Deadline First ◽

Time System ◽

Real Time System ◽

Main Target ◽

Migration Mechanism ◽

Simulation Results ◽

Earliest Deadline

In Real Time System, the achievement of deadline is the main target of every scheduling algorithm. Earliest Deadline First (EDF), Rate Monotonic (RM), and least Laxity First are some renowned algorithms that work well in their own context. As we know, there is a very common problem Domino's effect in EDF that is generated due to overloading condition (EDF is not working well in overloading situation). Similarly, performance of RM is degraded in underloading condition. We can say that both algorithms are complements of each other. Deadline missing in both events happens because of their utilization bounding strategy. Therefore, in this paper we are proposing a new scheduling algorithm that carries through the drawback of both existing algorithms. Joint EDF-RM scheduling algorithm is implemented in global scheduler that permits task migration mechanism in between processors in the system. In order to check the improved behavior of proposed algorithm we perform simulation. Results are achieved and evaluated in terms of Success Ratio (SR), Average CPU Utilization (ECU), Failure Ratio (FR), and Maximum Tardiness parameters. In the end, the results are compared with the existing (EDF, RM, and D_R_EDF) algorithms. It has been shown that the proposed algorithm performs better during overloading condition as well in underloading condition.

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