
The operations will continue until PyTorch/XLA encounters a barrier. This barrier can either be a [mark step()](https://github.com/pytorch/xla/blob/ff079bb48744e5aa6696201ccf34057f15fc7cac/torch_xla/core/xla_model.py#L751) api call or any other event which forces the execution of the graph recorded so far.

```python
xm.mark_step()
print(torch_xla._XLAC._get_xla_tensors_text([y1]))

Once the mark_step() is called, the graph is compiled and then executed on TPU, i.e. the tensors have been materialized. Therefore, the graph is now reduced to a single line y1 tensor which holds the result of the computation.
Compile Once, Execute Often