Benchmarking and Parallelization of Electrostatic Particle-In-Cell for low-temperature Plasma Simulation by particle-thread Binding

TL;DR

This paper introduces a novel particle-thread binding strategy for Particle-In-Cell plasma simulations that significantly improves parallel scalability and performance while maintaining compatibility with existing code structures.

Contribution

The paper presents a new parallelization approach for PIC simulations that reduces bottlenecks and enhances scalability using minimal code modifications.

Findings

Achieved near-linear scalability on 1000 cores.

Maintained data structure compatibility with existing PIC codes.

Demonstrated effectiveness on both shared and distributed memory systems.

Abstract

The Particle-In-Cell (PIC) method for plasma simulation tracks particle phase space information using particle and grid data structures. High computational costs in 2D and 3D device-scale PIC simulations necessitate parallelization, with the Charge Deposition (CD) subroutine often becoming a bottleneck due to frequent particle-grid interactions. Conventional methods mitigate dependencies by generating private grids for each core, but this approach faces scalability issues. We propose a novel approach based on a particle-thread binding strategy that requires only four private grids per node in distributed memory systems or four private grids in shared memory systems, enhancing CD scalability and performance while maintaining conventional data structures and requiring minimal changes to existing PIC codes. This method ensures complete accessibility of grid data structure for concurrent threads and avoids simultaneous access to particles within the same cell using additional functions and flags. Performance evaluations using a PIC benchmark for low-temperature partially magnetized E x B discharge simulation on a shared memory as well as a distributed memory system (1000 cores) demonstrate the method's scalability, and additionally, we show the method has little hardware dependency.