Performance optimizations for porting the openQ${}^{\star }$D package to GPUs

Abstract

OpenQ${}^{\star }$D code has been used by the RC${}^{\star }$ collaboration for the generation of fully dynamical QCD+QED gauge configurations with C${}^{\star }$ boundary conditions. In this talk, optimization of solvers provided with the openQ${}^{\star }$D package relevant for porting the code on GPU-accelerated supercomputing platforms is discussed. We present the analysis of the current implementations of the GCR solver preconditioned with Schwarz alternating procedure for ill-conditioned Dirac-operators. With the goal of enabling support for GPUs from various vendors, a novel method of adaptive CPU/GPU-hybrid implementation is proposed.