app.py

import gradio as gr
import spaces
import torch

zero = torch.Tensor([0]).cuda()
print(zero.device) # <-- 'cpu' 🤔

@spaces.GPU
def greet(n):
    print(zero.device) # <-- 'cuda:0' 🤗
    return n

counter = gr.State(value=0)

gr.Interface(
    fn=greet,
    inputs=[counter],
    outputs=[counter],
).launch()