HPSF Conference 2025

PETSc, the Portable, Extensible Toolkit for Scientific Computation, provides an extensive suite of scalable parallel solvers for linear and nonlinear equations, ordinary differential equation (ODE) integrators, and optimization algorithms. Widely adopted in both industry and academia, PETSc historically achieved performance portability through the C programming language and the Message Passing Interface (MPI) programming model. It used single-threaded MPI processes for both shared and distributed memory systems. This strategy had served us very well in the microprocessor age. However, the recent proliferation of accelerator-based architectures, particularly graphics processing units (GPUs), has posed new challenges to this performance portability. To address these challenges, we have integrated PETSc with the Kokkos ecosystem, specifically Kokkos-Core and Kokkos-Kernels. In this presentation, we describe our integration approach, highlight our experiences—both effective strategies and encountered challenges—and outline future developments aimed at further enhancing performance portability across evolving computational architectures.