Performance portable implementation of a kinetic plasma simulation mini-app

Performance portability is considered to be an inevitable requirementin the exascale era. We explore a performance portable approachfor fusion plasma turbulence simulation code employing kineticmodel, namely the GYSELA code. For this purpose, we extract thekey features of GYSELA such as the high dimensionality and the semi-Lagrangian scheme, and encapsulate them into a mini-application whichsolves the similar but a simplied Vlasov-Poisson system. We implementthe mini-app with a mixed OpenACC/OpenMP and Kokkos implementation,where we suppress unnecessary duplications of code lines. Fora reference case with the problem size of 1284, the Skylake (Kokkos),Nvidia Tesla P100 (OpenACC), and P100 (Kokkos) versions achieve anacceleration of 1.45, 12.95, and 17.83, respectively, with respect to thebaseline OpenMP version on Intel Skylake. In addition to the performanceportability, we discuss the code readability and productivity ofeach implementation. Based on our experience, Kokkos can oer a readableand productive code at the cost of initial porting eorts, whichwould be enormous for a large scale simulation code like GYSELA.SC1