expose sched.h functions (closes #12655)
diff --git a/Doc/library/os.rst b/Doc/library/os.rst
index 42dba30..47e6a1b 100644
--- a/Doc/library/os.rst
+++ b/Doc/library/os.rst
@@ -2744,6 +2744,155 @@
Availability: Unix.
+Interface to the scheduler
+--------------------------
+
+These functions control how a process is allocated CPU time by the operating
+system. They are only available on some Unix platforms. For more detailed
+information, consult your Unix manpages.
+
+.. versionadded:: 3.3
+
+The following scheduling policies are exposed if they are a supported by the
+operating system.
+
+.. data:: SCHED_OTHER
+
+ The default scheduling policy.
+
+.. data:: SCHED_BATCH
+
+ Scheduling policy for CPU-intensive processes that tries to preserve
+ interactivity on the rest of the computer.
+
+.. data:: SCHED_IDLE
+
+ Scheduling policy for extremely low priority background tasks.
+
+.. data:: SCHED_SPORADIC
+
+ Scheduling policy for sporadic server programs.
+
+.. data:: SCHED_FIFO
+
+ A First In First Out scheduling policy.
+
+.. data:: SCHED_RR
+
+ A round-robin scheduling policy.
+
+.. data:: SCHED_RESET_ON_FORK
+
+ This flag can OR'ed with any other scheduling policy. When a process with
+ this flag set forks, its child's scheduling policy and priority are reset to
+ the default.
+
+
+.. class:: sched_param(sched_priority)
+
+ This class represents tunable scheduling parameters used in
+ :func:`sched_setparam`, :func:`sched_setscheduler`, and
+ :func:`sched_getparam`. It is immutable.
+
+ At the moment, there is only one possible parameter:
+
+ .. attribute:: sched_priority
+
+ The scheduling priority for a scheduling policy.
+
+
+.. function:: sched_get_priority_min(policy)
+
+ Get the minimum priority value for *policy*. *policy* is one of the
+ scheduling policy constants above.
+
+
+.. function:: sched_get_priority_max(policy)
+
+ Get the maximum priority value for *policy*. *policy* is one of the
+ scheduling policy constants above.
+
+
+.. function:: sched_setscheduler(pid, policy, param)
+
+ Set the scheduling policy for the process with PID *pid*. A *pid* of 0 means
+ the calling process. *policy* is one of the scheduling policy constants
+ above. *param* is a :class:`sched_param` instance.
+
+
+.. function:: sched_getscheduler(pid)
+
+ Return the scheduling policy for the process with PID *pid*. A *pid* of 0
+ means the calling process. The result is one of the scheduling policy
+ constants above.
+
+
+.. function:: sched_setparam(pid, param)
+
+ Set a scheduling parameters for the process with PID *pid*. A *pid* of 0 means
+ the calling process. *param* is a :class:`sched_param` instance.
+
+
+.. function:: sched_getparam(pid)
+
+ Return the scheduling parameters as a :class:`sched_param` instance for the
+ process with PID *pid*. A *pid* of 0 means the calling process.
+
+
+.. function:: sched_rr_get_interval(pid)
+
+ Return the round-robin quantum in seconds for the process with PID *pid*. A
+ *pid* of 0 means the calling process.
+
+
+.. function:: sched_yield()
+
+ Voluntarily relinquish the CPU.
+
+
+.. class:: cpu_set(ncpus)
+
+ :class:`cpu_set` represents a set of CPUs on which a process is eligible to
+ run. *ncpus* is the number of CPUs the set should describe. Methods on
+ :class:`cpu_set` allow CPUs to be add or removed.
+
+ :class:`cpu_set` supports the AND, OR, and XOR bitwise operations. For
+ example, given two cpu_sets, ``one`` and ``two``, ``one | two`` returns a
+ :class:`cpu_set` containing the cpus enabled both in ``one`` and ``two``.
+
+ .. method:: set(i)
+
+ Enable CPU *i*.
+
+ .. method:: clear(i)
+
+ Remove CPU *i*.
+
+ .. method:: isset(i)
+
+ Return ``True`` if CPU *i* is enabled in the set.
+
+ .. method:: count()
+
+ Return the number of enabled CPUs in the set.
+
+ .. method:: zero()
+
+ Clear the set completely.
+
+
+.. function:: sched_setaffinity(pid, mask)
+
+ Restrict the process with PID *pid* to a set of CPUs. *mask* is a
+ :class:`cpu_set` instance.
+
+
+.. function:: sched_getaffinity(pid, size)
+
+ Return the :class:`cpu_set` the process with PID *pid* is restricted to. The
+ result will contain *size* CPUs.
+
+
.. _os-path:
Miscellaneous System Information