When testing if the prediction is correct after the model is transferring to script model, I found that the inference time is twice longer than pytorch model.
# pytorch 1.4, python 3.7
out1 = model(input) # forward time: 0.05 sec
ScriptModel = torch.jit.script(model, input)
out2 = ScriptModel(input) # forward time: 0.12 sec