From 1264a8f1089fad85cabb024c930b19b0a36864b4 Mon Sep 17 00:00:00 2001
From: Amar Takhar <amar@rtems.org>
Date: Sun, 17 Jan 2016 00:55:21 -0500
Subject: Split document into seperate files by section.

---
 posix_users/scheduler.rst | 192 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 192 insertions(+)
 create mode 100644 posix_users/scheduler.rst

(limited to 'posix_users/scheduler.rst')

diff --git a/posix_users/scheduler.rst b/posix_users/scheduler.rst
new file mode 100644
index 0000000..6c115e4
--- /dev/null
+++ b/posix_users/scheduler.rst
@@ -0,0 +1,192 @@
+Scheduler Manager
+#################
+
+Introduction
+============
+
+The scheduler manager ...
+
+The directives provided by the scheduler manager are:
+
+- ``sched_get_priority_min`` - Get Minimum Priority Value
+
+- ``sched_get_priority_max`` - Get Maximum Priority Value
+
+- ``sched_rr_get_interval`` - Get Timeslicing Quantum
+
+- ``sched_yield`` - Yield the Processor
+
+Background
+==========
+
+Priority
+--------
+
+In the RTEMS implementation of the POSIX API, the priorities range from
+the low priority of ``sched_get_priority_min()`` to the highest priority of``sched_get_priority_max()``. Numerically higher values represent higher
+priorities.
+
+Scheduling Policies
+-------------------
+
+The following scheduling policies are available:
+
+*SCHED_FIFO*
+    Priority-based, preemptive scheduling with no timeslicing. This is equivalent
+    to what is called "manual round-robin" scheduling.
+
+*SCHED_RR*
+    Priority-based, preemptive scheduling with timeslicing. Time quantums are
+    maintained on a per-thread basis and are not reset at each context switch.
+    Thus, a thread which is preempted and subsequently resumes execution will
+    attempt to complete the unused portion of its time quantum.
+
+*SCHED_OTHER*
+    Priority-based, preemptive scheduling with timeslicing. Time quantums are
+    maintained on a per-thread basis and are reset at each context switch.
+
+*SCHED_SPORADIC*
+    Priority-based, preemptive scheduling utilizing three additional parameters:
+    budget, replenishment period, and low priority. Under this policy, the
+    thread is allowed to execute for "budget" amount of time before its priority
+    is lowered to "low priority". At the end of each replenishment period,
+    the thread resumes its initial priority and has its budget replenished.
+
+Operations
+==========
+
+There is currently no text in this section.
+
+Directives
+==========
+
+This section details the scheduler manager’s directives.
+A subsection is dedicated to each of this manager’s directives
+and describes the calling sequence, related constants, usage,
+and status codes.
+
+sched_get_priority_min - Get Minimum Priority Value
+---------------------------------------------------
+.. index:: sched_get_priority_min
+.. index:: get minimum priority value
+
+**CALLING SEQUENCE:**
+
+.. code:: c
+
+    #include <sched.h>
+    int sched_get_priority_min(
+    int policy
+    );
+
+**STATUS CODES:**
+
+On error, this routine returns -1 and sets errno to one of the following:
+
+*EINVAL*
+    The indicated policy is invalid.
+
+**DESCRIPTION:**
+
+This routine return the minimum (numerically and logically lowest) priority
+for the specified ``policy``.
+
+**NOTES:**
+
+NONE
+
+sched_get_priority_max - Get Maximum Priority Value
+---------------------------------------------------
+.. index:: sched_get_priority_max
+.. index:: get maximum priority value
+
+**CALLING SEQUENCE:**
+
+.. code:: c
+
+    #include <sched.h>
+    int sched_get_priority_max(
+    int policy
+    );
+
+**STATUS CODES:**
+
+On error, this routine returns -1 and sets errno to one of the following:
+
+*EINVAL*
+    The indicated policy is invalid.
+
+**DESCRIPTION:**
+
+This routine return the maximum (numerically and logically highest) priority
+for the specified ``policy``.
+
+**NOTES:**
+
+NONE
+
+sched_rr_get_interval - Get Timeslicing Quantum
+-----------------------------------------------
+.. index:: sched_rr_get_interval
+.. index:: get timeslicing quantum
+
+**CALLING SEQUENCE:**
+
+.. code:: c
+
+    #include <sched.h>
+    int sched_rr_get_interval(
+    pid_t            pid,
+    struct timespec \*interval
+    );
+
+**STATUS CODES:**
+
+On error, this routine returns -1 and sets errno to one of the following:
+
+*ESRCH*
+    The indicated process id is invalid.
+
+*EINVAL*
+    The specified interval pointer parameter is invalid.
+
+**DESCRIPTION:**
+
+This routine returns the length of the timeslice quantum in the``interval`` parameter for the specified ``pid``.
+
+**NOTES:**
+
+The ``pid`` argument should be 0 to indicate the calling process.
+
+sched_yield - Yield the Processor
+---------------------------------
+.. index:: sched_yield
+.. index:: yield the processor
+
+**CALLING SEQUENCE:**
+
+.. code:: c
+
+    #include <sched.h>
+    int sched_yield( void );
+
+**STATUS CODES:**
+
+This routine always returns zero to indicate success.
+
+**DESCRIPTION:**
+
+This call forces the calling thread to yield the processor to another
+thread. Normally this is used to implement voluntary round-robin
+task scheduling.
+
+**NOTES:**
+
+NONE
+
+.. COMMENT: COPYRIGHT (c) 1988-2002.
+
+.. COMMENT: On-Line Applications Research Corporation (OAR).
+
+.. COMMENT: All rights reserved.
+
-- 
cgit v1.2.3