Maybe I should mention that I’m running windows 10.
Host memory limit is set to 1500 (default value) for the measurements in this post.
opencl_async_pixelpipe was set to false. This is apparently the default since I have not changed the config file.
Setting this parameter to true changes nothing except that the performance improved from 83,6 to 79,9 sec.
Now for your suggestions on opencl_memory_headroom (400 is the default)
opencl_memory_headroom=800 and opencl_async_pixelpipe=true
Contrast equalizer was now processed on GPU with tiling and total performance improved from 83,6 to 46,7 sec.
Contrast equalizer performance alone was improved from 39,4 sec on CPU to 4,4 sec on GPU.
Big success! But why?
Can you suggest other tunings?