[3.13] gh-125997: suggest efficient alternatives for time.sleep(0) (GH-128752) (#128984)

gh-125997: suggest efficient alternatives for `time.sleep(0)` (GH-128752)
(cherry picked from commit f4afaa6)

Co-authored-by: Bénédikt Tran <[email protected]>

Author: miss-islington

Doc/library/os.rst

@@ -5358,6 +5358,8 @@ information, consult your Unix manpages.
 The following scheduling policies are exposed if they are supported by the
 operating system.
 
+.. _os-scheduling-policy:
+
 .. data:: SCHED_OTHER
 
    The default scheduling policy.
@@ -5449,7 +5451,7 @@ operating system.
 
 .. function:: sched_yield()
 
-   Voluntarily relinquish the CPU.
+   Voluntarily relinquish the CPU. See :manpage:`sched_yield(2)` for details.
 
 
 .. function:: sched_setaffinity(pid, mask, /)

Doc/library/time.rst

@@ -385,6 +385,8 @@ Functions
    The suspension time may be longer than requested by an arbitrary amount,
    because of the scheduling of other activity in the system.
 
+   .. rubric:: Windows implementation
+
    On Windows, if *secs* is zero, the thread relinquishes the remainder of its
    time slice to any other thread that is ready to run. If there are no other
    threads ready to run, the function returns immediately, and the thread
@@ -393,12 +395,19 @@ Functions
    <https://learn.microsoft.com/windows-hardware/drivers/kernel/high-resolution-timers>`_
    which provides resolution of 100 nanoseconds. If *secs* is zero, ``Sleep(0)`` is used.
 
-   Unix implementation:
+   .. rubric:: Unix implementation
 
    * Use ``clock_nanosleep()`` if available (resolution: 1 nanosecond);
    * Or use ``nanosleep()`` if available (resolution: 1 nanosecond);
    * Or use ``select()`` (resolution: 1 microsecond).
 
+   .. note::
+
+      To emulate a "no-op", use :keyword:`pass` instead of ``time.sleep(0)``.
+
+      To voluntarily relinquish the CPU, specify a real-time :ref:`scheduling
+      policy <os-scheduling-policy>` and use :func:`os.sched_yield` instead.
+
    .. audit-event:: time.sleep secs
 
    .. versionchanged:: 3.5