Hi,
We did some investigation but so fat not have conclusion yet. It looks to be an issue in trt_inference.cpp. Seems like certain variables are global and when the parent process exits, the child process is dead, too. The issue is not seen in another similar samples:
/opt/nvidia/deepstream/deepstream-5.1/sources/apps/sample_apps/deepstream-test1/
/usr/src/tensorrt/samples/sampleOnnxMNIST/
Since you have mentioned DeepStream SDK is not considered in your usecase. Are you able to refer to sampleOnnxMNIST for further development?