Probabilistic real-time task scheduling method based on pWCET shaping

A technology of real-time tasks and scheduling methods, applied in the direction of program startup/switching, resource allocation, program control design, etc., can solve the problem of high computational complexity of schedulability analysis

Active Publication Date: 2018-11-20
DALIAN UNIV OF TECH
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Problems solved by technology

However, the complexity of response time analysis of probabilistic real-time systems is exponential with respect to the number of tasks and the number of values ​​estim...

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  • Probabilistic real-time task scheduling method based on pWCET shaping
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  • Probabilistic real-time task scheduling method based on pWCET shaping

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Embodiment Construction

[0044] An embodiment of the present invention will be further described below in conjunction with the accompanying drawings.

[0045] For example, there is a task set that contains two tasks: task τ 1 The period is T 1 = 5, the deadline is D 1 = 5, the probabilistic requirement of the task missing the deadline is pWCET is Task τ 2 The period is T 2 = 10, the deadline is D 2 = 10, the probability that the task misses the deadline is required to be pWCET is

[0046] Before introducing the embodiment of the present invention, we first use the Audsley algorithm for scheduling analysis to analyze whether the task set is schedulable.

[0047] First, because the task τ 2 The minimum WCET of 7 is greater than the task τ 1 deadline 5, and the task τ 1 The probabilistic demand for missing the deadline for is Known task τ 1 Priority is higher than τ 2 , and the task τ 1 The probabilistic response time of Such as figure 1 As shown, the task τ 1 Worst case executio...

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Abstract

The invention provides a probabilistic real-time task scheduling method based on pWCET (probabilistic worst case execution time) shaping, and belongs to the technical field of real-time systems. A probabilistic real-time task scheduling scheme based on the pWCET shaping is proposed, so that the goals of properly isolating the influence between probabilistic real-time tasks and lowering the calculation complexity of system schedulability analysis are achieved. According to the method, the pWCET of the probabilistic real-time tasks is shaped, and budget allocation is performed on the basis of the shaped pWCET, so that while the probabilistic real-time requirements of the tasks are met, the influence between the probabilistic real-time tasks can be properly isolated, and the schedulability ofthe whole task set is remarkably improved. In addition, the value of the shaped pWCET is obviously reduced compared with that of original pWCET; the calculation complexity of the schedulability analysis can be lowered; and the efficiency is remarkably improved.

Description

technical field [0001] The invention belongs to the technical field of real-time systems, and in particular relates to a probabilistic real-time task scheduling method based on probabilistic Worst Case Execution Time (pWCET) shaping. Background technique [0002] With the rapid development of chip technology, high-performance microprocessors are more and more widely used in safety-critical fields (such as avionics, automobiles, industrial control, etc.) . Although high-performance microprocessors can reduce the average execution time of tasks, due to the complexity of the processor architecture, the worst-case execution time (Worst Case Execution Time, WCET) of some tasks is relatively large, so a higher Over-provisioning to meet the real-time requirements of the system. In order to alleviate the problem of over-allocation, improve the utilization rate of resources, and meet the real-time requirements, a probabilistic method can be used to solve the uncertainty problem of ...

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Application Information

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IPC IPC(8): G06F9/48G06F9/50
CPCG06F9/4881G06F9/5038G06F2209/484G06F2209/5021
Inventor 任健康宿晓燕
Owner DALIAN UNIV OF TECH
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