During LGM @CarVac helped me understand how I can use OpenMP to accelerate filter performance.
https://github.com/PhotoFlare/photoflare/tree/openmp
Soon I will be working on this as a priority but only for certain filters. The logic is to split images into segments according to the number of threads and join the image after. This works for some filters that apply a large effect to every pixel but not filters that expect a whole image to be passed in.
Feel free to drop in any openMP with Graphicsmagick advice or comments!