Fault-Tolerant Real-Time Scheduling

Algorithmica ◽  
2000 ◽  
Vol 28 (1) ◽  
pp. 125-144 ◽  
Author(s):  
B. Kalyanasundaram ◽  
K. Pruhs
Keyword(s):  
Real Time ◽  
Fault Tolerant ◽  
Real Time Scheduling ◽  
Time Scheduling

Scheduling Mixed-Criticality Real-Time Tasks in a Fault-Tolerant System

2015 ◽  
Vol 6 (2) ◽  
pp. 65-86 ◽  
Author(s):  
Jian (Denny) Lin ◽  
Albert M. K. Cheng ◽  
Doug Steel ◽  
Michael Yu-Chi Wu ◽  
Nanfei Sun
Keyword(s):  
Real Time ◽  
Fault Tolerant ◽  
Formal Proof ◽  
Worst Case ◽  
Real Time Scheduling ◽  
Important Trend ◽  
Time Scheduling ◽  
On Line ◽  
Computer Tasks ◽  
Mixed Criticality

Enabling computer tasks with different levels of criticality running on a common hardware platform has been an increasingly important trend in the design of real-time and embedded systems. On such systems, a real-time task may exhibit different WCETs (Worst Case Execution Times) in different criticality modes. It is well-known that traditional real-time scheduling methods are not applicable to ensure the timely requirement of the mixed-criticality tasks. In this paper, the authors study a problem of scheduling real-time, mixed-criticality tasks with fault tolerance. An optimal, off-line algorithm is designed to guarantee the most tasks completing successfully when the system runs into the high-criticality mode. A formal proof of the optimality is given. Also, a novel on-line slack-reclaiming algorithm is proposed to recover from computing faults before the tasks' deadline during the run-time. Simulations show that an improvement of about 30% in performance is obtained by using the slack-reclaiming method.

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.

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