Comment by twtw

> if you tune well for one of them, the other one will suffer.

This is one of the things that bothers me the most about OpenCL. It attempts to offer this uniform abstraction over a generic compute accelerator, which can be CPU vector extensions, GPUs, or FPGAs, but these things are different enough that you have to develop for a specific type if you want reasonable performance. So you get none of the benefits of a accelerator specific abstraction while still writing accelerator specific code.

There is a real cost to a generic abstraction, and distinct languages/platforms would in my mind be better than different "dialects" of the same language/platform that pretend to be compatible but really aren't.

I like that CUDA is very clearly designed to run only on GPUs - it provides a clarity that OpenCL lacks.