Timing rtTrace via NVAPI

Yes, you can simply use the CUDA clock() instruction for that and scale it accordingly.

Please find more information and links to example code in this post where I mentioned that blog post as well:
https://forums.developer.nvidia.com/t/optix-6-5-wireframe-rendering/119619/10

Actually the OptiX SDKs before 7.0.0 also had that feature inside the pinhole_camera.cu example. Search for TIME_VIEW.