scholarly journals Utilization Bound Scheduling Analysis for Nonpreemptive Uniprocessor Architecture Using UML-RT

2014 ◽  
Vol 2014 ◽  
pp. 1-11
Author(s):  
S. Ewins Pon Pushpa ◽  
Manamalli Devasigamani
Keyword(s):  
Release Time ◽  
Periodic Tasks ◽  
Task Set ◽  
Processor Utilization ◽  
Window Analysis ◽  
Rate Monotonic ◽  
Utilization Bound ◽  
Priority Scheme ◽  
Schedulability Test ◽  
Necessary And Sufficient

The key for adopting the utilization-based schedulability test is to derive the utilization bound. Given the computation times, this paper proposes two utilization bound algorithms to derive interrelease times for nonpreemptive periodic tasks, using a new priority scheme, “Rate Monotonic Algorithm-Shortest Job First.” The obtained task set possesses the advantage of Rate Monotonic Algorithm and Shortest Job First priority scheme. Further, the task set is tested for schedulability, by first deriving a general schedulability condition from “problem window” analysis and, a necessary and sufficient schedulability condition for a task to be scheduled, at any release time are also derived. As a technical contribution, success ratio and effective processor utilization are analyzed for our proposed utilization bound algorithms on a uniprocessor architecture modeled using UML-RT.

scholarly journals Schedulability of Rate Monotonic Algorithm using Improved Time Demand Analysis for Multiprocessor Environment

2018 ◽  
Vol 8 (1) ◽  
pp. 429
Author(s):  
Leena Das ◽  
Sourav Mohapatra ◽  
Durga Prasad Mohapatra
Keyword(s):  
Real Time ◽  
Scheduling Algorithm ◽  
Demand Analysis ◽  
Priority Scheduling ◽  
Task Set ◽  
Rate Monotonic ◽  
Test Algorithm ◽  
Task Sets ◽  
Number Of Iterations ◽  
Better Than

<p>Real-Time Monotonic algorithm (RMA) is a widely used static priority scheduling algorithm. For application of RMA at various systems, it is essential to determine the system’s feasibility first. The various existing algorithms perform the analysis by reducing the scheduling points in a given task set. In this paper we propose a schedubility test algorithm, which reduces the number of tasks to be analyzed instead of reducing the scheduling points of a given task. This significantly reduces the number of iterations taken to compute feasibility. This algorithm can be used along with the existing algorithms to effectively reduce the high complexities encountered in processing large task sets. We also extend our algorithm to multiprocessor environment and compare number of iterations with different number of processors. This paper then compares the proposed algorithm with existing algorithm. The expected results show that the proposed algorithm performs better than the existing algorithms.</p>

Utilization bound for periodic task set with composite deadline

2010 ◽  
Vol 36 (6) ◽  
pp. 1101-1109 ◽  
Author(s):  
Nasro Min-Allah ◽  
Ishtiaq Ali ◽  
Jiansheng Xing ◽  
Yongji Wang
Keyword(s):  
Task Set ◽  
Periodic Task ◽  
Utilization Bound

Scheduling of Periodic Tasks with Data Dependency on Multiprocessors

2013 ◽  
Vol 756-759 ◽  
pp. 2131-2136
Author(s):  
Jin Lin Wang
Keyword(s):  
Time Constraints ◽  
Release Time ◽  
Data Dependency ◽  
Scheduling Problem ◽  
Periodic Tasks ◽  
Dataflow Graphs ◽  
Time Limits ◽  
Static Schedule ◽  
Data Constraints ◽  
Synchronous Dataflow Graphs

This article studies the scheduling problem of a set of tasks with time or data constraints on a number of identical processors with full connections. We present an algorithm, in which a set of static schedule lists can be obtained, each for a processor, such that each task starts executing after its release time and completes its computation before its deadline, and all the precedence relations between tasks resulting from data dependency are satisfied. The data dependency relations between tasks are represented by Synchronous Dataflow Graphs (SDF) as they can indicate tasks concurrency and enable effective scheduling on multiprocessor platforms. The SDF, however, does not support the time constraints of tasks directly, thus an adaption is applied to conform to the time limits. With this adaption, the periodic tasks of implicit-deadline or constrained-deadline can be scheduled on multiprocessor platform effectively.

scholarly journals A Task Parameter Inference Framework for Real-Time Embedded Systems

Electronics ◽  
2019 ◽  
Vol 8 (2) ◽  
pp. 116
Author(s):  
Namyong Jung ◽  
Hyeongboo Baek ◽  
Jinkyu Lee
Keyword(s):  
Embedded Systems ◽  
Real Time ◽  
Dynamic Properties ◽  
Interval Length ◽  
Static Properties ◽  
Periodic Tasks ◽  
Task Set ◽  
In The Beginning ◽  
Task Parameters ◽  
Task Parameter

While recent studies addressed security attacks in real-time embedded systems, most of them assumed prior knowledge of parameters of periodic tasks, which is not realistic under many environments. In this paper, we address how to infer task parameters, from restricted information obtained by simple system monitoring. To this end, we first develop static properties that are independent of inference results and therefore applied only once in the beginning. We further develop dynamic properties each of which can tighten inference results by feeding an update of the inference results obtained by other properties. Our simulation results demonstrate that the proposed inference framework infers task parameters for RM (Rate Monotonic) with reasonable tightness; the ratio of exactly inferred task periods is 95.3% and 65.6%, respectively with low and high task set use. The results also discover that the inference performance varies with the monitoring interval length and the task set use.

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