网络分区和避免竞争
Network Partitioning and Avoidable Contention
摘要：
网络争用经常支配并行算法的运行时间并限制缩放性能。大多数以前的研究减轻或消除竞争，利用几种方法之一：通信最小化算法;热点避免路由方案;拓扑感知的任务映射;或提高全球网络的属性，如二分带宽，边扩展，分区，和网络直径。实际上，并行作业通常只使用主机系统的一小部分。处理器分配策略如何影响分区内的争用？我们利用网络图的边等周分析来确定网络分区是否具有最优的内部二分法。增加二等分允许更有效地使用网络资源，减少或完全消除链路争用。我们首先研究环面网络和分区的几何特征，最大限度地提高内部二分法带宽。我们研究了Mira和JUQUEEN的分配策略，这两个最大的公开访问的基于Blue Gene/Q torus的超级计算机。我们的分析表明，其当前分区的二分带宽通常可以通过改变分区的几何形状来提高。对于争用受限的工作负载，这些可以产生高达X2的加速比。基准测试实验验证了预测。我们的分析适用于其他网络的分配策略。
英文摘要：
Network contention frequently dominates the run time of parallel algorithms and limits scaling performance. Most previous studies mitigate or eliminate contention by utilizing one of several approaches: communication-minimizing algorithms; hotspot-avoiding routing schemes; topology-aware task mapping; or improving global network properties, such as bisection bandwidth, edge-expansion, partitioning, and network diameter. In practice, parallel jobs often use only a fraction of a host system. How do processor allocation policies affect contention within a partition? We utilize edge-isoperimetric analysis of network graphs to determine whether a network partition has optimal internal bisection. Increasing the bisection allows a more efficient use of the network resources, decreasing or completely eliminating the link contention. We first study torus networks and characterize partition geometries that maximize internal bisection bandwidth. We examine the allocation policies of Mira and JUQUEEN, the two largest publicly-accessible Blue Gene/Q torus-based supercomputers. Our analysis demonstrates that the bisection bandwidth of their current partitions can often be improved by changing the partitions' geometries. These can yield up to a X2 speedup for contention-bound workloads. Benchmarking experiments validate the predictions. Our analysis applies to allocation policies of other networks.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
