I am creating a computer vision application that detect objects via a web camera. I am currently focusing on the performance of the application My problem is in a part of the application that generates the XML cascade file using Haartraining file. This is very slow and takes about 6days . To get around this problem I decided to use multiprocessing, to minimize the total time to generate Haartraining XML file. I found two solutions: opencl and (openMp and openMPI ) . Now I'm confused about which one to use. I read that opencl is to use multiple cpu and GPU but on the same machine. Is that so? On the other hand OpenMP is for multi-processing and using openmpi we can use multiple CPUs over the network. But OpenMP has no GPU support. Can you please suggest the pros and cons of using either of the libraries.