节能调度算法设计是高性能计算领域中的一个研究热点.复制调度算法能够减少后继任务等待延时,缩短任务总体调度时间,但是耗费了更多的能量.为此,作者提出一种启发式处理器合并优化方法 PRO.该方法按照任务最早开始时间和最早结束时间查找处理器时间空隙,将轻负载处理器上的任务重新分配到其它处理器上,从而减少使用的处理器数目,降低系统总体能耗.实验结果表明,和已有的复制任务调度算法TDS、EAD和PEBD相比,优化后的调度算法在不增加调度时间的条件下,能够明显减少使用的处理器数和系统总体能耗,从而更好地实现性能和能耗之间的平衡.
The design of energy-efficient scheduling algorithms has become a hot research topic in high performance computing.To shorten schedule length of parallel tasks with precedence constraints,scheduling algorithms could duplicate tasks on critical paths to avoid communication delay caused by inter-task dependence.However,task duplications incur more energy consumption.In this paper,we propose a heuristic Processor Reduction Optimizing(PRO) approach to reduce the number of processors used to run parallel tasks,thereby decreasing system energy consumption.The PRO approach can find appropriate time slots to accommodate tasks from low-utilized processors according to their earliest start time and earliest complete time.Extensive experimental results show that the proposed PRO approach,compared to existing duplication-based scheduling algorithms,such as Task Duplication Scheduling(TDS),Energy-Aware Duplication(EAD) and Performance-Energy Balanced Duplication(PEBD) algorithms,can effectively decrease the number of used processors and save energy without performance degradation.