NVIDIA vs. AMD OpenCL Linux Benchmarks With Darktable 2.2

Given this weekend's release of Darktable 2.2 as a big upgrade to this open-source RAW photo workflow software, here are some fresh benchmarks of NVIDIA GeForce and AMD Radeon graphics cards under Linux when making use of the program's OpenCL support, which did see some improvements during this v2.2 cycle.