How to evaluate GPU utilization(usage) on Windows?

Thanks a lot! nvidia-smi.exe seems always displaying the righte GPU usage as I tried, this is cool.

I would like to let you know that the GPU usage in Windows Task-Manager is not right when the games are using the GPU engines besides “3D” engine, this confusing me a lot, I`d rather think that this is a bug in Windows system.

but who/what decides which GPU engine to use?