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Title: Balancing Particle and Mesh Computation in a Particle-In-Cell Code

Conference ·
OSTI ID:1295135
 [1];  [1];  [2];  [2];  [3];  [2]
  1. ORNL
  2. Princeton Plasma Physics Laboratory (PPPL)
  3. Rensselaer Polytechnic Institute (RPI)

The XGC1 plasma microturbulence particle-in-cell simulation code has both particle-based and mesh-based computational kernels that dominate performance. Both of these are subject to load imbalances that can degrade performance and that evolve during a simulation. Each separately can be addressed adequately, but optimizing just for one can introduce significant load imbalances in the other, degrading overall performance. A technique has been developed based on Golden Section Search that minimizes wallclock time given prior information on wallclock time, and on current particle distribution and mesh cost per cell, and also adapts to evolution in load imbalance in both particle and mesh work. In problems of interest this doubled the performance on full system runs on the XK7 at the Oak Ridge Leadership Computing Facility compared to load balancing only one of the kernels.

Research Organization:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Oak Ridge Leadership Computing Facility (OLCF)
Sponsoring Organization:
USDOE Office of Science (SC)
DOE Contract Number:
AC05-00OR22725
OSTI ID:
1295135
Resource Relation:
Conference: CUG 2016, London, United Kingdom, 20160508, 20160512
Country of Publication:
United States
Language:
English