subprocess.Popen.wait doc: mention asyncio to avoid busy loop
diff --git a/Doc/library/subprocess.rst b/Doc/library/subprocess.rst
index 1a9dd9d..f03c322 100644
--- a/Doc/library/subprocess.rst
+++ b/Doc/library/subprocess.rst
@@ -629,6 +629,12 @@
:exc:`TimeoutExpired` exception. It is safe to catch this exception and
retry the wait.
+ .. note::
+
+ The function is implemented using a busy loop (non-blocking call and
+ short sleeps). Use the :mod:`asyncio` module for an asynchronous wait:
+ see :class:`asyncio.create_subprocess_exec`.
+
.. warning::
This will deadlock when using ``stdout=PIPE`` and/or