【摘要】 大规模并行计算机互连网络的设计对并行应用程序的执行效率有重要影响,k-元n-立方体是广泛使用的拓扑结构.局部通信是并行应用的主要通信模式之一,研究局部通信模式下互连网络的性能有重要意义,已有分析模型缺乏对这方面的充分研究.引入局部通信率和局部通信区域半径组成的二元参数,刻画k-元n-立方体网络节点间通信的空间局部性.利用排队论对网络建模,研究延迟和吞吐量随负载的变化规律,比较局部性参数对网络性能的影响强度,针对长、短消息情况分别进行详细讨论.最后采用改进的网络模拟器,验证分析模型具有较高的准确性.为具有局部通信性质的大规模并行应用,提供了一种有效预测延迟和吞吐量的方法.更多还原

【Abstract】 Interconnection network is a key component of parallel computer which influences the parallel application’s efficiency significantly.k-ary n-cube network topology is widely adopted in many current large scale parallel computers such as Blue Gene/L and Cray XT4.The method of spatial communication locality is implied in many real parallel programs,but as we know the exiting analytical models just gave some rough and fragmented results on network performance under communication locality.The binary parameters,local message fraction and local domain’s radius,are proposed to measure parallel application’s spatial communication locality.Then based on queueing theory,an analytical model of the k-ary n-cube is established to evaluate communication locality’s impact on message latency and network throughput.The situation that the message’s length is shorter than the network radius is discussed,which has not been considered in the existing analytical models.The impacts of different parameters on network performance are compared carefully.At last,an improved network simulator is used to validate the analytical model,and it is demonstrated that the analytical results close to the simulation experiments well.The proposed model gives an efficient method to predict message latency and network throughput of large scale parallel applications whose communication patterns have local character.更多还原