I beg to differ,
In most cases Cross Fire works by distributing whole frames. E.g. in a two GPUs scenario all even frames will be rendered on GPU 0 and all odd numbered frames will be rendered on GPU 1 .
Currently we do not support OGL interop with multi-device contexts.
However, you do not need OGL to maximize parallelism.
You need to remove CPU-GPU synchronizations. Be sure to en-queue and flush the NDrange commands of frame N+1 before waiting for the results of frame N .
You can profile GPU utilization by using AMD APP Profiler or Microsoft GPUView.