并行处理中节点间通信对加速比的影响

Influence of communication between nodes on the speed-up ratio in parallel processing

加速比是衡量并行处理性能的重要指标之一;较高加速比的获得除与任务的划分、并行算法的选择等有关外,还与各节点间的通信有关;在大多数并行系统中,在数据规模确定的情况下,程序的加速比随节点数的增加而增加,但是大多数机群系统的节点间是共享物理传输介质的,这就使得许多并行程序的加速比在节点数目超过某一个值之后会随着节点数的增加而减少;文章通过数值实验研究,分析了节点间通信对加速比的影响,进一步论证了节点间通信对加速比的重要影响。

The speed-up ratio is one of the key indexes of parallel processing,and gaining of a higher speed-up ratio has relation not only with the partition of tasks and the selection of parallel algorithms but also with the communication between nodes. In most parallel systems, when the data size of parallel programs is fixed,the speed-up ratio increases with the increase of the total number of nodes. But in most clusters of nodes, all nodes share one physical transmission media, as a result,the speed-up ratio of most parallel programs decreases with the increase of nodes when the total number of nodes exceeds a score.In this paper,the influence of communication between nodes is investigated by experiment,and the obtained result further confirms the affection of communication between nodes.