Dynamic Scheduling of Skippable Periodic Tasks in Weakly-Hard Real-Time Systems

2007 ◽  
Author(s):  
Maryline Chetto ◽  
Audrey Marchand
Keyword(s):  
Real Time ◽  
Dynamic Scheduling ◽  
Real Time Systems ◽  
Periodic Tasks ◽  
Hard Real Time ◽  
Time Systems

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.

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