In 3.11 we added a "CFrame" struct that sits on the C stack. This struct held a pointer to the current frame, and a "use_tracing" field.
Since we needed to check this field on every bytecode dispatch, it was very hot and needed to be on the C stack for performance.

With PEP 669, that field is gone and there is no need for the "CFrame" any more. We should remove it and revert to the keeping a pointer to the current frame in the thread state.

Linked PRs

• GH-108035: Remove the _PyCFrame struct as it is no longer needed for performance. #108036