use larger blockDim(1024) and smaller sharedMem(8196), occupancy is poor but performance is better
use larger blockDim(1024) and smaller sharedMem(8196), occupancy is poor
but performance is better

yszheda/CUDA-knn-MPI,yszheda/OpenCL-knn-1GPU,yszheda/OpenCL-knn-1GPU,yszheda/CUDA-knn-1GPU