Design of an Extenics-based Scheduler in a Dual-Processor Real-Time System

• Main Authors: Chih-Hung Hung, 洪志宏
• Other Authors: Liang-Teh Lee
• Format: Others
• Language: zh-TW
• Published: 2002
• Online Access: http://ndltd.ncl.edu.tw/handle/03793215264257636946

碩士 === 大同大學 === 資訊工程研究所 === 90 === Operating systems that produce correct responses within a definite time limit and can finish tasks before the deadline are called Real-Time Operating Systems (RTOS). General speaking, RTOS usually implemented in the form of embedded system. We usually estimate the performance of RTOS by how many tasks could be scheduled and finish tasks before the deadline. The scheduling algorithm is the key point to decide the performance for RTOS. Because tasks are created periodically and sporadically in the real world, a RTOS cannot operate effectively by single scheduling algorithm. In this thesis, based on the extenics scheduling algorithm, we propose a more complete method to fit situations in the real world. In the dual-processor architecture and communication between processors, RTOS can schedule all tasks and meet all tasks’ deadline with extenics-based scheduling. By using Extension Dependent Function to predict which task could finish before the deadline or not in the default processor, and use feedback mechanism to reallocate miss deadline tasks to the other processor. The advantage of this method may not use complex scheduling algorithms; this method is the better choice for cost/performance. From experimental results, use dual-processor with Extenics-based scheduling algorithm is more efficient than other scheduling algorithms, and to meet the requirements in the real world.