scholarly journals Weakly-hard Real-time Guarantees for Earliest Deadline First Scheduling of Independent Tasks

2020 ◽  
Vol 18 (6) ◽  
pp. 1-25
Author(s):  
Zain A. H. Hammadeh ◽  
Sophie Quinton ◽  
Rolf Ernst
Keyword(s):  
Real Time ◽  
Earliest Deadline First ◽  
Hard Real Time ◽  
Earliest Deadline ◽  
Independent Tasks

Energy efficient fault-tolerant earliest deadline first scheduling for hard real-time systems

2014 ◽  
Vol 50 (5-6) ◽  
pp. 592-619 ◽  
Author(s):  
Qiushi Han ◽  
Linwei Niu ◽  
Gang Quan ◽  
Shaolei Ren ◽  
Shangping Ren
Keyword(s):  
Real Time ◽  
Energy Efficient ◽  
Fault Tolerant ◽  
Earliest Deadline First ◽  
Real Time Systems ◽  
Hard Real Time ◽  
Time Systems ◽  
Earliest Deadline

A Scheduling Extension Scheme of the Earliest Deadline First Policy for Hard Real-Time Uniprocessor Systems Integrated on Posix Threads Based on Linux

2018 ◽  
Vol 33 (1) ◽  
pp. 31-40
Author(s):  
Vidblain Amaro-Ortega ◽  
Arnoldo D韆z-Ram韗ez ◽  
Brenda Leticia Flores-R韔s ◽  
F閘ix Fernando Gonz醠ez-Navarro ◽  
Frank Werner ◽  
...  
Keyword(s):  
Real Time ◽  
Earliest Deadline First ◽  
Posix Threads ◽  
Hard Real Time ◽  
Uniprocessor Systems ◽  
Earliest Deadline

Analysis on Scheduling Algorithms of Real-Time Hybrid Tasks

2014 ◽  
Vol 644-650 ◽  
pp. 2253-2257
Author(s):  
Jian Lang Wu ◽  
Jing Kai Shi ◽  
Yi Bin Wang
Keyword(s):  
Real Time ◽  
Earliest Deadline First ◽  
Real Time Systems ◽  
Extended Version ◽  
Periodic Tasks ◽  
Aperiodic Tasks ◽  
Hard Real Time ◽  
Uniprocessor Systems ◽  
Time Systems ◽  
Earliest Deadline

In real-time systems, periodic tasks and aperiodic tasks exist simultaneously. In a uniprocessor system, mainly there are Deferrable Server algorithm (DS) [1], Slack Stealing algorithm (SSA) [2] and their extended version for software/hardware hybrid real-time task scheduling. DS algorithm sets a high priority periodic task server to provide services for aperiodic tasks, while SSA algorithm computes tasks unoccupied time offline, and then schedule aperiodic tasks during the unoccupied period. The two algorithms are both proposed for soft real-time tasks, reducing the response time of the real-time tasks, but cannot guarantee that these aperiodic real-time tasks received can meet deadlines. In this paper, through combination of DS algorithm and EDF (Earliest Deadline First) algorithm [6], a new algorithm called DS-EDF is introduced, which can scheduling hard real-time aperiodic tasks on the DS server. This algorithm is not only suitable for uniprocessor systems, but also has the ability to extend to multiprocessor systems.

The Global Limited Preemptive Earliest Deadline First Feasibility of Sporadic Real-Time Tasks

2014 ◽  
Author(s):  
Abhilash Thekkilakattil ◽  
Sanjoy Baruah ◽  
Radu Dobrin ◽  
Sasikumar Punnekkat
Keyword(s):  
Real Time ◽  
Earliest Deadline First ◽  
Earliest Deadline

Energy-Efficient Scheduling for Embedded Real-Time Systems Using Threshold Work-Demand Analysis

2017 ◽  
Vol 26 (06) ◽  
pp. 1750091 ◽  
Author(s):  
Linwei Niu ◽  
Wei Li
Keyword(s):  
Energy Saving ◽  
Real Time ◽  
Energy Efficient ◽  
Critical Speed ◽  
Demand Analysis ◽  
Real Time Systems ◽  
Work Demand ◽  
Hard Real Time ◽  
Time Systems ◽  
Earliest Deadline

In this paper, we study the problem of reducing the energy consumption for hard real-time systems scheduled according to either fixed-priority (FP) or earliest-deadline-first (EDF) scheme. To balance the static and dynamic energy consumptions, the concept of critical speed was proposed in previous research. Moreover, when combined with the processor idle/shutdown state, the critical speed was widely used as the lower bound for voltage scaling in literature. In this paper, we show that this strategy might not always be more energy efficient than the traditional DVS strategy and there exists a dynamic tradeoff between these two strategies depending on the job’s work-demand to be finished within certain intervals. To effectively address this issue, we propose a unified approach that combines these two strategies to achieve better overall energy saving performance. Our approach determines the energy-efficient speeds for real-time jobs in their corresponding feasible intervals based on the threshold work-demand analysis. Our experimental results demonstrate that the proposed techniques significantly outperform previous approaches in the overall energy saving performance.

ACO Based Dynamic Scheduling Algorithm for Real-Time Multiprocessor Systems

2013 ◽  
pp. 85-96
Author(s):  
Apurva Shah ◽  
Ketan Kotecha
Keyword(s):  
Real Time ◽  
Computational Models ◽  
Dynamic Scheduling ◽  
Scheduling Algorithm ◽  
Earliest Deadline First ◽  
Multiprocessor Systems ◽  
Individual Agent ◽  
Collective Foraging ◽  
Time Systems ◽  
Earliest Deadline

The Ant Colony Optimization (ACO) algorithms are computational models inspired by the collective foraging behavior of ants. The ACO algorithms provide inherent parallelism, which is very useful in multiprocessor environments. They provide balance between exploration and exploitation along with robustness and simplicity of individual agent. In this paper, ACO based dynamic scheduling algorithm for homogeneous multiprocessor real-time systems is proposed. The results obtained during simulation are measured in terms of Success Ratio (SR) and Effective CPU Utilization (ECU) and compared with the results of Earliest Deadline First (EDF) algorithm in the same environment. It has been observed that the proposed algorithm is very efficient in underloaded conditions and it performs very well during overloaded conditions also. Moreover, the proposed algorithm can schedule some typical instances successfully which are not possible to schedule using EDF algorithm.

scholarly journals Thermal Analysis of Fair Scheduling in Real-time Embedded Systems

2018 ◽  
Vol 7 (1) ◽  
pp. 48
Author(s):  
Tayyaba Bokhari ◽  
Sajjad Haider Shami ◽  
Farhan Haseeb
Keyword(s):  
Real Time ◽  
Thermal Management ◽  
System Reliability ◽  
Operating Temperature ◽  
Multiprocessor Scheduling ◽  
Earliest Deadline First ◽  
Fair Scheduling ◽  
The Past ◽  
Reliability Performance ◽  
Earliest Deadline

Over the past few decades, increased demand of highly sophisticated real-time applications with complex functionalities has directly led to exponentially increased power consumption and significantly elevated system temperatures. These elevated temperature and thermal variations present formidable challenges towards system reliability, performance, cooling cost and leakages. This article explores the thermal management strength of two fairness based algorithms, namely Proportional Fair (PFair) and Deadline Partitioning Fair (DP-Fair). In related literature, the introduction of fairness is often considered as a tool to achieve optimality in multiprocessor scheduling algorithms. This work shows that these algorithms bring about better thermal profile when compared with the commonly used Earliest Deadline First (EDF) algorithm in similar conditions both in uniprocessor and multiprocessor environments. A simulation is conducted for periodic task set model. The obtained results are encouraging and show that use of fairness based algorithms reduces the operating temperature, peak temperature, and thermal variations.

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