A performance and energy evaluation of many-light rendering algorithms

Recently, the performance of many-light algorithms, where thousands of light sources are used to compute the lighting in a scene, has improved so much that they have reached the realm of real-time rendering. In general, the algorithm that is considered “best” is the one that is the fastest in terms of time per frame. Given that power efficiency may become or already is one of the most important optimization factors for both hardware and software vendors for graphics, we take a different route and instead measure both energy usage per frame and frame time for a number of popular many-light rendering algorithms on an Intel Iris Pro. We use Pareto frontiers for each configuration to examine the possibilities for trade-offs between rendering time and energy consumption. Furthermore, we examine the optimal algorithms at each configuration, and are able to draw generalized conclusions on when each algorithm is most efficient. We also record several other statistics on the algorithms, e.g., bandwidth, and are able to draw further conclusions with regard to energy consumption