Low-Cost Load Balancing for Parallel Particle-in-Cell Simulations with Thick Overlapping Layers
Low-Cost Load Balancing for Parallel Particle-in-Cell Simulations with Thick Overlapping Layers
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DOI：
10.1109/trustcom.2013.134
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发表时间：
2013-07
期刊：
影响因子：
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通讯作者：
Y. Miyake;H. Nakashima
中科院分区：
文献类型：
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作者：
Y. Miyake;H. Nakashima
本文介绍了一种并行实现我们的实际粒子在细胞（PIC）模拟器与OhHelp动态负载平衡算法。虽然代码并行化基于简单的块域分解，但OhHelp通过使每个计算节点帮助另一个重负载节点来实现负载平衡，从而实现粒子数量方面的可扩展性。除了OhHelp应用程序之外，为了最小化OhHelp的开销成本，在每个子域的边界之外新引入了与相邻域重叠的许多附加层。优化可以大大降低节点之间的粒子传输的开销成本，但它会导致每个节点负责的域大小的增加。尽管有这种权衡功能，重叠层连接和进一步的低级别优化发挥1.8倍的PIC模拟器性能的改善。因此，优化的模拟器表现出良好的可扩展性和稳定的并行执行效率，使用高达4096个核心，显示出3%的小并行效率退化从16- 4096-核心并行执行。
This paper describes a parallel implementation of our practical particle-in-cell (PIC) simulator with the OhHelp dynamic load-balancing algorithm. Although the code parallelization is based on simple block domain decomposition, OhHelp accomplishes load balancing and thus the scalability in terms of the number of particles by making each computation node help another heavily loaded node. In addition to the OhHelp application, a number of additional layers overlapping with adjacent domains are newly introduced outside the boundaries of each subdomain for the purpose of minimizing overhead costs of OhHelp. The optimization can drastically reduce overhead costs for particle transfer among nodes, whereas it leads to increase in domain size which each node is responsible for. Despite this trade-off feature, the overlapping layer attachment and a further lower-level optimization exert 1.8-fold improvement of the PIC simulator performance. Consequently, the optimized simulator exhibits a good scalability and a stable efficiency in parallel executions using up to 4096 cores, showing small parallel efficiency degradation of 3% from 16- to 4096-core parallel executions.