Graphic cards (GPUs), initially used for graphic processing, have a highly parallel architecture. Innovations in both architecture and programming languages opened the new domain of GPGPU where GPUs are used as accelerators for general purpose HPC applications. Our main objective is to facilitate the use of these new architectures for high-performance computing needs; our research follows two main directions. The first direction concerns an automatic code transformation from a high level code into an equivalent low level one, capable of running on accelerators. To this end we implemented a code transformer that can handle parallel ''for'' loops (single or nested) of an OpenMP code and convert it into an equivalent CUDA code, which is in a human readable form that allows for further optimizations. Moreover, the future of HPC lies in distributed architectures based on hybrid nodes. Specific programming schemes have to be used in order to allow users to benefit from such multiGPU nodes. We conducted a comparative study which revealed that using OpenMP threads is the most adequate way to control multiple graphic cards as well as manage communications efficiently within a multiGPU node.
A HIGH-LEVEL PARALLEL DEVELOPMENT FRAMEWORK FOR GRAPHIC ACCELERATORS: AN IMPLEMENTATION BASED ON OPENMP