Comment on "A pre-run-time scheduling algorithm for hard real-time systems"

1997 ◽  
Vol 23 (9) ◽  
pp. 599-600 ◽  
Author(s):  
T.F. Abdelzaher ◽  
K.G. Shin
Keyword(s):  
Real Time ◽  
Scheduling Algorithm ◽  
Real Time Systems ◽  
Time Scheduling ◽  
Run Time ◽  
Hard Real Time ◽  
Time Systems

Reconfiguration of Synchronous Real-Time Operating System

2013 ◽  
Vol 2 (1) ◽  
pp. 114-132 ◽  
Author(s):  
Hamza Gharsellaoui ◽  
Mohamed Khalgui ◽  
Samir Ben Ahmed
Keyword(s):  
Real Time ◽  
Systems Engineering ◽  
Scheduling Algorithm ◽  
User Requirements ◽  
Real Time Systems ◽  
Real Time Scheduling ◽  
Temporal Properties ◽  
Time Scheduling ◽  
Run Time ◽  
Time Systems

Real-time scheduling is the theoretical basis of real-time systems engineering. Earliest Deadline first (EDF) is an optimal scheduling algorithm for uniprocessor real-time systems. The paper deals with Reconfigurable Uniprocessor embedded Real-Time Systems classically implemented by different OS tasks that the authors suppose independent, synchronous and periodic to meet functional and temporal properties described in user requirements. They define two forms of automatic reconfigurations which are applied at run-time: Addition-Remove of tasks or just modifications of their temporal parameters: WCET and/or Periods. The authors define a new semantic of the reconfiguration where a crucial criterion to consider is the automatic improvement of the system’s feasibility at run-time by using an Intelligent Agent that automatically checks the system’s feasibility after any reconfiguration scenario to verify if all tasks meet the required deadlines. To handle all possible reconfiguration solutions, the authors propose an agent-based architecture that applies automatic reconfigurations to re-obtain the system’s feasibility and satisfy user requirements. Therefore, they developed the tool RT-Reconfiguration to support these contributions that they apply on the running example system and the authors apply the Real-Time Simulator, Cheddar to check the whole system behavior and evaluate the performance of the algorithm. They present simulations of this architecture where the agent that implemented is evaluated.

A pre-run-time scheduling algorithm for object-based distributed real-time systems

1999 ◽  
Vol 45 (14) ◽  
pp. 1169-1188 ◽  
Author(s):  
I Santhoshkumar ◽  
G Manimaran ◽  
C Siva Ram Murthy
Keyword(s):  
Real Time ◽  
Scheduling Algorithm ◽  
Real Time Systems ◽  
Object Based ◽  
Time Scheduling ◽  
Run Time ◽  
Time Systems

Evaluation of a flexible task scheduling algorithm for distributed hard real-time systems

1985 ◽  
Vol C-34 (12) ◽  
pp. 1130-1143 ◽  
Author(s):  
John A. Stankovic ◽  
Krithivasan Ramamritham ◽  
Shengchang Cheng
Keyword(s):  
Real Time ◽  
Task Scheduling ◽  
Scheduling Algorithm ◽  
Real Time Systems ◽  
Task Scheduling Algorithm ◽  
Hard Real Time ◽  
Time Systems

A static scheduling algorithm for distributed hard real-time systems

1991 ◽  
Vol 3 (3) ◽  
pp. 227-246 ◽  
Author(s):  
J. P. C. Verhoosel ◽  
E. J. Luit ◽  
D. K. Hammer ◽  
E. Jansen
Keyword(s):  
Real Time ◽  
Scheduling Algorithm ◽  
Real Time Systems ◽  
Static Scheduling ◽  
Hard Real Time ◽  
Time Systems

scholarly journals Task-Level Re-Execution Framework for Improving Fault Tolerance on Symmetry Multiprocessors

Symmetry ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 651 ◽  
Author(s):  
Hyeongboo Baek ◽  
Jaewoo Lee
Keyword(s):  
Real Time ◽  
Fault Tolerant ◽  
Target System ◽  
Real Time Systems ◽  
Software Faults ◽  
Real Time Scheduling ◽  
Time Scheduling ◽  
Hard Real Time ◽  
Deployed Systems ◽  
Time Systems

Hard real-time systems are employed in military, aeronautics, and astronautics fields where deployed systems are susceptible to software faults that can result in functional errors. Thus, there is a need to use fault-tolerant (FT) real-time scheduling. Among the various fault-tolerant real-time scheduling techniques, re-execution has been applied widely to existing real-time systems owing to its simplicity and applicability. However, re-execution requires multiple executions of every task, and some tasks miss their deadlines owing to the prolonged execution time; therefore, it has been found to be suitable for only soft real-time systems. In this paper, we propose an FT policy that can be incorporated into most (if not all) existing real-time scheduling algorithms on multiprocessor systems, which improves the reliability of the target system without a tradeoff against schedulability. As a case study, we apply the FT policy to existing fixed-priority scheduling and earliest deadline zero-laxity scheduling, and we demonstrate that it enhances reliability without schedulability loss.

New Hybrid Genetic Based Approach for Real-Time Scheduling of Reconfigurable Embedded Systems

2018 ◽  
Vol 10 (1) ◽  
pp. 23-36
Author(s):  
Ibrahim Gharbi ◽  
Hamza Gharsellaoui ◽  
Sadok Bouamama
Keyword(s):  
Embedded System ◽  
Real Time ◽  
Scheduling Algorithm ◽  
Journal Article ◽  
Real Time Systems ◽  
Software Faults ◽  
Real Time Scheduling ◽  
Time Scheduling ◽  
Algorithmic Approaches ◽  
Time Systems

This journal article deals with the problem of real-time scheduling of operating systems (OS) tasks by a hybrid genetic-based scheduling algorithm. Indeed, most of real-time systems are framed with aid of priority-based scheduling algorithms. Nevertheless, when such a scenario is applied to save the system at the occurrence of hardware-software faults, or to improve its performance, some real-time properties can be violated at run-time. In contrast, most of the applications of real-time systems are based on timing constraints, i.e. OS tasks should be scheduled properly to finish their execution within the time specified by the real-time systems. For this reason, the authors propose in their article, a hybrid genetic-based scheduling approach that automatically checks the systems feasibility after any reconfiguration scenario was applied to an embedded system. A benchmark example is given, and the experimental results demonstrate the effectiveness of the originally proposed genetic-based scheduling approach over other such classical genetic algorithmic approaches.

A Fault-Tolerant Scheduling Algorithm Based on Checkpointing and Redundancy for Distributed Real-Time Systems

2019 ◽  
Vol 10 (3) ◽  
pp. 58-75 ◽  
Author(s):  
Barkahoum Kada ◽  
Hamoudi Kalla
Keyword(s):  
Real Time ◽  
Fault Tolerant ◽  
Scheduling Algorithm ◽  
Real Time Systems ◽  
Transient Faults ◽  
Spare Capacity ◽  
Tolerance Approach ◽  
Architecture Simulation ◽  
Hard Real Time ◽  
Time Systems

Real-time systems are becoming ever more widely used in life-critical applications, and the need for fault-tolerant scheduling can only grow in the years ahead. This article presents a novel fault tolerance approach for tolerating transient faults in hard real-time systems. The proposed approach combines both checkpointing with rollback and active replication to tolerate several transient faults. Based on this approach, a new static fault-tolerant scheduling algorithm SFTS is presented. It is based on a list of scheduling heuristics which satisfy the application time constraints even in the presence of faults by exploring the spare capacity of available processors in the architecture. Simulation results show the performance and effectiveness of the proposed approach compared to other fault-tolerant approaches. The results reveal that in the presence of multiple transient faults, the average timing overhead of this approach is lower than checkpointing technique. Moreover, the proposed algorithm SFTS achieves better feasibility rate in the presence of multiple transient faults.

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