Video playing carton(not smoothly) with Qt QLabel on high utilization rate of GPU

I run the video analysis service on one process, and provide service with RESTful Web API, and the app and the service are running on separate processes, they communicate with HTTP post method. The video analysis has a ResNet-101 neural network inference with TensorRT framework, and is very time and GPU costly.
I have a video analysis app develop with Qt. I display the video with QLabel, to avoid Qt GUI to be freezed, i read video frames from file on another thread, and update the QLabel video frame via Qt signal and slots periodically(every 33 milliseconds). And i request the video frame analysis with HTTP post and wait for the response on another thread again. So read video frame from file, requst analysis service and GUI display are on separate threads.
When the app run, the video can not playing smoothly, and i can see GPU utilization rate is high(tegrastats output shows that GR3D_FREQ often above 98%).
When i deploy the video analysis service process on the other machine and connect via ethernet, the video playing carton disappeared.
So when running the service and app on the same machine, how can i limit the GPU utilization rate of the analysis service to let the app playing video smoothly?

We don’t have interface to limit GPU utilization rate.

Nut sure if it helps, but you may try to set priority of each process:
https://linux.die.net/man/3/setpriority

Thanks DaneLLL, I have tried it, but it has not improved.