scholarly journals Schedulability Analysis for Rate Monotonic Algorithm-Shortest Job First Using UML-RT

2014 ◽  
Vol 2014 ◽  
pp. 1-10
Author(s):  
S. Ewins Pon Pushpa ◽  
Manamalli Devasikamani
Keyword(s):  
Real Time ◽  
Early Stage ◽  
Schedulability Analysis ◽  
Target System ◽  
System Modelling ◽  
Modelling Language ◽  
Time System ◽  
Real Time System ◽  
Unified Modelling Language ◽  
Rate Monotonic

System modelling with a unified modelling language (UML) is an active research area for developing real-time system development. UML is widely used modelling language in software engineering community, to specify the requirement, and analyse the target system successfully. UML can be used to provide multiple views of the system under design with the help of a variety of structural and behavioural diagrams at an early stage. UML-RT (unified modelling language-real time) is a language used to build an unambiguous executable specification of a real-time system based on UML concepts. This paper presents a unified modeling approach for a newly proposed rate monotonic scheduling algorithm-shortest job first (RMA-SJF) for partitioned, semipartitioned and global scheduling strategies in multiprocessor architecture using UML-RT for different system loads. As a technical contribution, effective processor utilization of individual processors and success ratio are analyzed for various scheduling principles and compared with EDF and D_EDF to validate our proposal.

Fault-Tolerant Strategy for Real-Time System Based on Evolvable Hardware

2017 ◽  
Vol 26 (07) ◽  
pp. 1750111 ◽  
Author(s):  
Jie Wang ◽  
Jiwei Liu
Keyword(s):  
Real Time ◽  
Recovery Time ◽  
Fault Tolerant ◽  
Fault Tree Analysis ◽  
Repair Process ◽  
Evolvable Hardware ◽  
Target System ◽  
Time System ◽  
Real Time System ◽  
Fault Tolerant System

The evolvable hardware (EHW) is widely used in the design of fault-tolerant system. Fault-tolerant system is really a real-time system, and the recovery time is necessary in fault detection and recovery. However, when applying EHW, real-time characteristic is usually ignored. In this paper, a fault-tolerant strategy based on EHW is proposed. The recovery time, predicted by the fault tree analysis (FTA), is considered as a constraint condition. A configuration library is set up in the design phase to accelerate the repair process of the anticipated faults. An evolvable algorithm (EA) based on similarity is applied to evolve the repair circuit for the unanticipated faults. When the library reaches the upper, the target system is reconfigured by the EA-repair technology. Extensive experiments are conducted to show that our method can improve the fault-tolerance of the system while satisfying the real-time requirement on FPGA platform. In a long run system, our method can keep a higher fault recovery rate.

scholarly journals Limited Non-Preemptive EDF Scheduling for a Real-Time System with Symmetry Multiprocessors

Symmetry ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 172 ◽  
Author(s):  
Hoyoun Lee ◽  
Jinkyu Lee
Keyword(s):  
Real Time ◽  
Scheduling Algorithm ◽  
Schedulability Analysis ◽  
Timing Constraints ◽  
Limited Information ◽  
Time System ◽  
Real Time System ◽  
System A ◽  
The Future ◽  
Earliest Deadline

In a real-time system, a series of jobs invoked by each task should finish its execution before its deadline, and EDF (Earliest Deadline First) is one of the most popular scheduling algorithms to meet such timing constraints of a set of given tasks. However, EDF is known to be ineffective in meeting timing constraints for non-preemptive tasks (which disallow any preemption) when the system does not know the future job release patterns of the tasks. In this paper, we develop a scheduling algorithm for a real-time system with a symmetry multiprocessor platform, which requires only limited information about the future job release patterns of a set of non-preemptive tasks, called LCEDF. We then derive its schedulability analysis that provides timing guarantees of the non-preemptive task set on a symmetry multiprocessor platform. Via simulations, we demonstrate the proposed schedulability analysis for LCEDF significantly improves the schedulability performance in meeting timing constraints of a set of non-preemptive tasks up to 20.16%, compared to vanilla non-preemptive EDF.

A Scalable Approach to Real-Time System Timing Applications

2010 ◽  
pp. 606-644
Author(s):  
Alan Grigg ◽  
Lin Guan
Keyword(s):  
Real Time ◽  
Reference Model ◽  
Timing Analysis ◽  
Target System ◽  
Time System ◽  
Worst Case ◽  
Real Time System ◽  
Resource Requirements ◽  
Time Scheduling ◽  
Execution Model

This chapter describes a real-time system performance analysis approach known as reservation-based analysis (RBA). The scalability of RBA is derived from an abstract (target-independent) representation of system software components, their timing and resource requirements and run-time scheduling policies. The RBA timing analysis framework provides an evolvable modeling solution that can be instigated in early stages of system design, long before the software and hardware components have been developed, and continually refined through successive stages of detailed design, implementation and testing. At each stage of refinement, the abstract model provides a set of best-case and worst-case timing ‘guarantees’ that will be delivered subject to a set of scheduling ‘obligations’ being met by the target system implementation. An abstract scheduling model, known as the rate-based execution model then provides an implementation reference model with which compliance will ensure that the imposed set of timing obligations will be met by the target system.

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