Considering the disadvantage of first-fit strategy in fault-tolerant rate-monotonic first-fit （FTRMFF） algorithm, we analyze the slack time of processors and the schedulability of periodic tasks in rate-monotonic ...Considering the disadvantage of first-fit strategy in fault-tolerant rate-monotonic first-fit （FTRMFF） algorithm, we analyze the slack time of processors and the schedulability of periodic tasks in rate-monotonic （RM） algorithm. Then, the RM-based idleness factor and compact factor are presented to quantify the compact degree of tasks assigned to the same processor. In this paper, the novel fault-tolerant rate-monotonic compact-factor-driven （FTRMCFD） algorithm, which follows the principle of compact factor maximal when allocating the processors for tasks, is proposed. FTRMCFD algorithm makes every processor contain more tasks and get higher utilization to increase the schedulability performance of distributed systems. The simulation experiments reveal that FTRMCFD can reduce the number of required processors by up to 11.5% （with an average of 5.3%）.展开更多
This paper presents an optimal checkpoint strategy for fault-tolerance in real-time systems where transient faults occur in Poisson distribution. In our environment, multiple real-time tasks with different deadlines a...This paper presents an optimal checkpoint strategy for fault-tolerance in real-time systems where transient faults occur in Poisson distribution. In our environment, multiple real-time tasks with different deadlines and harmonic periods are scheduled in the system by rate-monotonic algorithm, and checkpoints are inserted at a constant interval in each task. When a fault is detected, the system carries out rollback to the latest checkpoint and re-executes tasks. The maximum number of re-executable checkpoints and an equation to check schedulability are derived, and the optimal number of checkpoints is selected to maximize the probability of completing all the tasks within their deadlines.展开更多
基金Supported by the National Natural Science Foundation of China (60603032)
文摘Considering the disadvantage of first-fit strategy in fault-tolerant rate-monotonic first-fit （FTRMFF） algorithm, we analyze the slack time of processors and the schedulability of periodic tasks in rate-monotonic （RM） algorithm. Then, the RM-based idleness factor and compact factor are presented to quantify the compact degree of tasks assigned to the same processor. In this paper, the novel fault-tolerant rate-monotonic compact-factor-driven （FTRMCFD） algorithm, which follows the principle of compact factor maximal when allocating the processors for tasks, is proposed. FTRMCFD algorithm makes every processor contain more tasks and get higher utilization to increase the schedulability performance of distributed systems. The simulation experiments reveal that FTRMCFD can reduce the number of required processors by up to 11.5% （with an average of 5.3%）.
文摘This paper presents an optimal checkpoint strategy for fault-tolerance in real-time systems where transient faults occur in Poisson distribution. In our environment, multiple real-time tasks with different deadlines and harmonic periods are scheduled in the system by rate-monotonic algorithm, and checkpoints are inserted at a constant interval in each task. When a fault is detected, the system carries out rollback to the latest checkpoint and re-executes tasks. The maximum number of re-executable checkpoints and an equation to check schedulability are derived, and the optimal number of checkpoints is selected to maximize the probability of completing all the tasks within their deadlines.
