Performance evaluations of gyrokinetic Eulerian code GT5D on massively parallel multi-core platforms

Idomura, Yasuhiro   ; Jolliet, S.*

Plasma turbulence simulations based on the five dimensional (5D) gyrokinetic equation, which is the first principle model of fusion plasmas, are standard tools in analyzing turbulent transport phenomena. However, 5D turbulence simulations at the ITER size requires extreme scale computation, and therefore, an efficient use of massively parallel computers has been an important issue in computational fusion science. In GT5D, which is a 5D Eulerian code developed by JAEA, 5D phase space is parallelized using multi-dimensional domain decomposition based on physical symmetry properties of the equation system. By implementing this parallel model on a multilayer network consisting of multiple MPI communicators and a SMP layer, the scalability is highly improved, and the sustained performance of Tflops is achieved on 16384 cores of BX900.