From my experience with CUDA, parallelism doesn't require any functional like programming. CUDA is very non functional from my perspective since parallel units

From my experience with CUDA, parallelism doesn't require any functional like programming. CUDA is very non functional from my perspective since parallel units of work have no return values and their only way of persisting information is to write to a global namespace. Also parallel algorithms are often clever and sometimes take advantage of domain specific details to cut corners for more performance. It seems to me that eventually people will have to use a more complex programming model to get past performance hits. One question is whether the majority of programmers will encounter performance hits in the future