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Diffstat (limited to 'posix_users/scheduler.rst')
| -rw-r--r-- | posix_users/scheduler.rst | 111 |
1 files changed, 63 insertions, 48 deletions
diff --git a/posix_users/scheduler.rst b/posix_users/scheduler.rst index 9d249b0..68eefc0 100644 --- a/posix_users/scheduler.rst +++ b/posix_users/scheduler.rst @@ -1,3 +1,7 @@ +.. COMMENT: COPYRIGHT (c) 1988-2002. +.. COMMENT: On-Line Applications Research Corporation (OAR). +.. COMMENT: All rights reserved. + Scheduler Manager ################# @@ -8,13 +12,13 @@ The scheduler manager ... The directives provided by the scheduler manager are: -- ``sched_get_priority_min`` - Get Minimum Priority Value +- sched_get_priority_min_ - Get Minimum Priority Value -- ``sched_get_priority_max`` - Get Maximum Priority Value +- sched_get_priority_max_ - Get Maximum Priority Value -- ``sched_rr_get_interval`` - Get Timeslicing Quantum +- sched_rr_get_interval_ - Get Timeslicing Quantum -- ``sched_yield`` - Yield the Processor +- sched_yield_ - Yield the Processor Background ========== @@ -22,8 +26,9 @@ 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 +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 @@ -32,8 +37,8 @@ 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. + 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 @@ -46,11 +51,12 @@ The following scheduling policies are available: 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. + 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 ========== @@ -60,10 +66,11 @@ 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. +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: sched_get_priority_min - Get Minimum Priority Value --------------------------------------------------- @@ -72,29 +79,34 @@ sched_get_priority_min - Get Minimum Priority Value **CALLING SEQUENCE:** -.. code:: c +.. code-block:: c #include <sched.h> int sched_get_priority_min( - int policy + int policy ); **STATUS CODES:** -On error, this routine returns -1 and sets errno to one of the following: +On error, this routine returns -1 and sets ``errno`` to one of the following: -*EINVAL* - The indicated policy is invalid. +.. list-table:: + :class: rtems-table + + * - ``EINVAL`` + - The indicated policy is invalid. **DESCRIPTION:** -This routine return the minimum (numerically and logically lowest) priority -for the specified ``policy``. +This routine return the minimum (numerically and logically lowest) priority for +the specified ``policy``. **NOTES:** NONE +.. _sched_get_priority_max: + sched_get_priority_max - Get Maximum Priority Value --------------------------------------------------- .. index:: sched_get_priority_max @@ -102,19 +114,22 @@ sched_get_priority_max - Get Maximum Priority Value **CALLING SEQUENCE:** -.. code:: c +.. code-block:: c #include <sched.h> int sched_get_priority_max( - int policy + int policy ); **STATUS CODES:** -On error, this routine returns -1 and sets errno to one of the following: +On error, this routine returns -1 and sets ``errno`` to one of the following: + +.. list-table:: + :class: rtems-table -*EINVAL* - The indicated policy is invalid. + * - ``EINVAL`` + - The indicated policy is invalid. **DESCRIPTION:** @@ -125,6 +140,8 @@ for the specified ``policy``. NONE +.. _sched_rr_get_interval: + sched_rr_get_interval - Get Timeslicing Quantum ----------------------------------------------- .. index:: sched_rr_get_interval @@ -132,32 +149,37 @@ sched_rr_get_interval - Get Timeslicing Quantum **CALLING SEQUENCE:** -.. code:: c +.. code-block:: c #include <sched.h> int sched_rr_get_interval( - pid_t pid, - struct timespec \*interval + pid_t pid, + struct timespec *interval ); **STATUS CODES:** -On error, this routine returns -1 and sets errno to one of the following: +On error, this routine returns -1 and sets ``errno`` to one of the following: -*ESRCH* - The indicated process id is invalid. +.. list-table:: + :class: rtems-table -*EINVAL* - The specified interval pointer parameter is invalid. + * - ``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``. +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: + sched_yield - Yield the Processor --------------------------------- .. index:: sched_yield @@ -165,7 +187,7 @@ sched_yield - Yield the Processor **CALLING SEQUENCE:** -.. code:: c +.. code-block:: c #include <sched.h> int sched_yield( void ); @@ -177,16 +199,9 @@ 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. +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. - |