Scaling of 3D game engine workloads on modern multi-GPU systems

This work supposes a first attempt to characterize the 3D game workload running on commodity multi-GPU systems. Depending on the rendering workload balance mode used, the intra and interframe dependencies due to render-to-texture require a number of synchronizations that can significantly impact the scalability with multiple GPUs. In this paper, a proprietary analytical tool called EMPATHY has been used to evaluate, for a set popular DX9 games, the performance of both classic split frame and alternate frame rendering modes as well as combined modes supporting more than 4 GPUs. We have also evaluated the application of the early copy and concurrent update techniques together as alternative to delayed surface copy of render-to-texture surfaces, showing a 48% percent improvement for some workloads.