scholarly journals Extending Task-level to Job-level Fixed Priority Assignment and Schedulability Analysis Using Pseudo-deadlines

2012 ◽  
Author(s):  
Hoon Sung Chwa ◽  
Hyoungbu Back ◽  
Sanjian Chen ◽  
Jinkyu Lee ◽  
Arvind Easwaran ◽  
...  
Keyword(s):  
Schedulability Analysis ◽  
Priority Assignment ◽  
Fixed Priority ◽  
Job Level ◽  
Task Level

A Review of Sufficient Schedulability Analysis for Fixed Priority Scheduling Systems

2015 ◽  
Vol 741 ◽  
pp. 856-859
Author(s):  
Yan Feng Zhai ◽  
Feng Xiang Zhang
Keyword(s):  
Schedulability Analysis ◽  
Priority Assignment ◽  
Priority Scheduling ◽  
Fixed Priority ◽  
Fixed Priority Scheduling ◽  
Rate Monotonic ◽  
Simple Implementation ◽  
Deadline Monotonic ◽  
Activation Rates

This papercarries out a survey of sufficient schedulability analysis forfixed priority (FP) scheduling. The most common used fixed priority assignment is the rate monotonic (RM) algorithm, according to its policy, the task priorities are ordered based on their activation rates, so that the task with the shortest period is assigned the highest priority. However, when each task’s relative deadline is not equal to its period, the RM algorithm is not suitable to assign the task priorities. When relative deadlines are less than or equal to periods,the deadline monotonic (DM) algorithm can be deployed to schedule the tasks. The utilization based schedulability analysis has the advantage of simple implementation, and manyexisting schedulability analyses on uniprocessor are covered.

scholarly journals Assigning Priorities for Fixed Priority Preemption Threshold Scheduling

2015 ◽  
Vol 2015 ◽  
pp. 1-14 ◽  
Author(s):  
Saehwa Kim
Keyword(s):  
Real Time ◽  
Empirical Evaluation ◽  
Priority Assignment ◽  
Fixed Priority ◽  
Assignment Algorithm ◽  
Optimal Priority Assignment ◽  
A Performance

Preemption threshold scheduling (PTS) enhances real-time schedulability by controlling preemptiveness of tasks. This benefit of PTS highly depends on a proper algorithm that assigns each task feasible scheduling attributes, which are priority and preemption threshold. Due to the existence of an efficient optimal preemption threshold assignment algorithm that works with fully assigned priority orderings, we need an optimal priority assignment algorithm for PTS. This paper analyzes the inefficiency or nonoptimality of the previously proposed optimal priority assignment algorithms for PTS. We develop theorems for exhaustively but safely pruning infeasible priority orderings while assigning priorities to tasks for PTS. Based on the developed theorems, we correct the previously proposed optimal priority assignment algorithm for PTS. We also propose a performance improved optimal priority assignment algorithm for PTS proving its optimality. The empirical evaluation results clearly show the effectiveness of the proposed algorithm.

A Review of Hierarchical Fixed Priority Scheduling

2014 ◽  
Vol 536-537 ◽  
pp. 566-569
Author(s):  
Feng Xiang Zhang
Keyword(s):  
Real Time ◽  
Schedulability Analysis ◽  
Priority Scheduling ◽  
Scheduling Policies ◽  
Fixed Priority ◽  
Fixed Priority Scheduling ◽  
Priority Algorithms ◽  
Priority Systems ◽  
Real Time Applications ◽  
Global And Local

This paper focus on two level hierarchical scheduling where several real-time applications are scheduled by the fixed priority algorithms. The application with its real-time tasks is bound to a server which can be modeled as a sporadic task with special care for the schedulability analysis. Different scheduling policies and servers can be applied for hierarchical fixed priority systems, this paper gives a closer review of schedulability analysis for applications and tasks when the global and local schedulers of a system are fixed priority.

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