Real-Time Rendering with Heterogeneous GPUS

Over the years, the performance demand for graphics applications has been steadily increasing. While upgrading the hardware is one direct solution, the emergence of the new lowlevel and low-overhead graphics APIs like Vulkan also exposed the possibility of improving rendering performance from the bottom of software implementation. Most of the recent years’ middle- to high-end personal computers are equipped with both integrated and discrete GPUs. However, with previous graphics APIs, it is hard to put these two heterogeneous GPUs to work concurrently in the same application without tailored driver support. This thesis provides an exploration into the utilization of such heterogeneous GPUs in realtime rendering with the help of Vulkan API. This paper first demonstrates the design and implementation details for the proposed heterogeneous GPUs working model. After that, the paper presents the test of two workload offloading strategies: offloading screen space output workload to the integrated GPU and offloading asynchronous computation workload to the integrated GPU. While this study failed to obtain performance improvement through offloading screen space output workload, it is successful in validating that offloading asynchronous computation workload from the discrete GPU to the integrated GPU can improve the overall system performance. This study proves that it is possible to make use of the integrated and discrete GPUs concurrently in the same application with the help of Vulkan. And offloading asynchronous computation workload from the discrete GPU to the integrated GPU can provide up to 3-4% performance improvement with combinations like UHD Graphics 630 + RTX 2070 Max-Q and HD Graphics 630 + GTX 1050