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Sebastian Huber
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c-user/config/general.rst
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c-user/config/general.rst
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.. SPDX-License-Identifier: CC-BY-SA-4.0
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.. Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
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General System Configuration
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============================
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This section defines the general system configuration options supported by
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``<rtems/confdefs.h>``.
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.. index:: CONFIGURE_DIRTY_MEMORY
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.. _CONFIGURE_DIRTY_MEMORY:
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CONFIGURE_DIRTY_MEMORY
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----------------------
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CONSTANT:
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``CONFIGURE_DIRTY_MEMORY``
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DATA TYPE:
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Boolean feature macro.
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RANGE:
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Defined or undefined.
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DEFAULT VALUE:
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By default, the memory used by the RTEMS Workspace and the C Program Heap
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is uninitialized memory.
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DESCRIPTION:
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This macro indicates whether RTEMS should dirty the memory used by the
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RTEMS Workspace and the C Program Heap as part of its initialization. If
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defined, the memory areas are dirtied with a ``0xCF`` byte pattern.
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Otherwise, they are not.
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NOTES:
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Dirtying memory can add significantly to system boot time. It may assist in
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finding code that incorrectly assumes the contents of free memory areas is
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cleared to zero during system initialization. In case
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:ref:`CONFIGURE_ZERO_WORKSPACE_AUTOMATICALLY` is also defined, then the
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memory is first dirtied and then zeroed.
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.. index:: CONFIGURE_EXTRA_TASK_STACKS
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.. index:: memory for task tasks
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.. _CONFIGURE_EXTRA_TASK_STACKS:
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CONFIGURE_EXTRA_TASK_STACKS
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---------------------------
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CONSTANT:
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``CONFIGURE_EXTRA_TASK_STACKS``
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DATA TYPE:
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Unsigned integer (``size_t``).
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RANGE:
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Undefined or positive.
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DEFAULT VALUE:
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The default value is 0.
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DESCRIPTION:
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This configuration parameter is set to the number of bytes the applications
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wishes to add to the task stack requirements calculated by
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``<rtems/confdefs.h>``.
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NOTES:
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This parameter is very important. If the application creates tasks with
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stacks larger then the minimum, then that memory is NOT accounted for by
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``<rtems/confdefs.h>``.
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.. index:: CONFIGURE_INITIAL_EXTENSIONS
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.. _CONFIGURE_INITIAL_EXTENSIONS:
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CONFIGURE_INITIAL_EXTENSIONS
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----------------------------
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CONSTANT:
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``CONFIGURE_INITIAL_EXTENSIONS``
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DATA TYPE:
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List of user extension initializers (``rtems_extensions_table``).
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RANGE:
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Undefined or a list of one or more user extensions.
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DEFAULT VALUE:
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This is not defined by default.
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DESCRIPTION:
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If ``CONFIGURE_INITIAL_EXTENSIONS`` is defined by the application, then
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this application specific set of initial extensions will be placed in the
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initial extension table.
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NOTES:
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None.
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.. index:: CONFIGURE_INTERRUPT_STACK_SIZE
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.. index:: interrupt stack size
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.. _CONFIGURE_INTERRUPT_STACK_SIZE:
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CONFIGURE_INTERRUPT_STACK_SIZE
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------------------------------
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CONSTANT:
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``CONFIGURE_INTERRUPT_STACK_SIZE``
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DATA TYPE:
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Unsigned integer.
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RANGE:
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Positive.
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DEFAULT VALUE:
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The default value is ``BSP_INTERRUPT_STACK_SIZE`` in case it is defined,
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otherwise the default value is ``CPU_STACK_MINIMUM_SIZE``.
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DESCRIPTION:
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The ``CONFIGURE_INTERRUPT_STACK_SIZE`` configuration option defines the
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size of an interrupt stack in bytes.
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NOTES:
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The interrupt stack size must be aligned according to
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``CPU_INTERRUPT_STACK_ALIGNMENT``.
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There is one interrupt stack available for each configured processor
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(:ref:`CONFIGURE_MAXIMUM_PROCESSORS <CONFIGURE_MAXIMUM_PROCESSORS>`). The
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interrupt stack areas are statically allocated in a special linker section
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(``.rtemsstack.interrupt``). The placement of this linker section is
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BSP-specific.
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Some BSPs use the interrupt stack as the initialization stack which is used
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to perform the sequential system initialization before the multithreading
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is started.
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The interrupt stacks are covered by the :ref:`stack checker
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<CONFIGURE_STACK_CHECKER_ENABLED>`. However, using a too small interrupt
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stack size may still result in undefined behaviour.
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In releases before RTEMS 5.1 the default value was
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:ref:`CONFIGURE_MINIMUM_TASK_STACK_SIZE
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<CONFIGURE_MINIMUM_TASK_STACK_SIZE>` instead of ``CPU_STACK_MINIMUM_SIZE``.
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.. index:: CONFIGURE_MAXIMUM_FILE_DESCRIPTORS
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.. index:: maximum file descriptors
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.. _CONFIGURE_MAXIMUM_FILE_DESCRIPTORS:
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CONFIGURE_MAXIMUM_FILE_DESCRIPTORS
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----------------------------------
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CONSTANT:
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``CONFIGURE_MAXIMUM_FILE_DESCRIPTORS``
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DATA TYPE:
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Unsigned integer (``uint32_t``).
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RANGE:
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Zero or positive.
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DEFAULT VALUE:
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If ``CONFIGURE_APPLICATION_NEEDS_CONSOLE_DRIVER`` is defined, then the
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default value is 3, otherwise the default value is 0. Three file
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descriptors allows RTEMS to support standard input, output, and error I/O
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streams on ``/dev/console``.
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DESCRIPTION:
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This configuration parameter is set to the maximum number of file like
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objects that can be concurrently open.
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NOTES:
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None.
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.. index:: CONFIGURE_MAXIMUM_PRIORITY
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.. index:: maximum priority
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.. index:: number of priority levels
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.. _CONFIGURE_MAXIMUM_PRIORITY:
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CONFIGURE_MAXIMUM_PRIORITY
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--------------------------
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CONSTANT:
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``CONFIGURE_MAXIMUM_PRIORITY``
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DATA TYPE:
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Unsigned integer (``uint8_t``).
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RANGE:
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Valid values for this configuration parameter must be one (1) less than
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than a power of two (2) between 4 and 256 inclusively. In other words,
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valid values are 3, 7, 31, 63, 127, and 255.
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DEFAULT VALUE:
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The default value is 255, because RTEMS must support 256 priority levels to
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be compliant with various standards. These priorities range from zero (0)
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to 255.
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DESCRIPTION:
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For the schedulers
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* :ref:`SchedulerPriority`, which is the default in uniprocessor
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configurations and can be configured through the
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:ref:`CONFIGURE_SCHEDULER_PRIORITY` configuration option,
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* :ref:`SchedulerSMPPriority` which can be configured through the
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:ref:`CONFIGURE_SCHEDULER_PRIORITY_SMP` configuration option, and
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* :ref:`SchedulerSMPPriorityAffinity` which can be configured through the
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:ref:`CONFIGURE_SCHEDULER_PRIORITY_AFFINITY_SMP` configuration option
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this configuration option specifies the maximum numeric priority of any task
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for these schedulers and one less that the number of priority levels for
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these schedulers. For all other schedulers provided by RTEMS, this
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configuration option has no effect.
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NOTES:
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The numerically greatest priority is the logically lowest priority in the
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system and will thus be used by the IDLE task.
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Priority zero (0) is reserved for internal use by RTEMS and is not available
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to applications.
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Reducing the number of priorities through this configuration option reduces
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the amount of memory allocated by the schedulers listed above. These
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schedulers use a chain control structure per priority and this structure
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consists of three pointers. On a 32-bit architecture, the allocated memory
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is 12 bytes * (``CONFIGURE_MAXIMUM_PRIORITY`` + 1), e.g. 3072 bytes for 256
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priority levels (default), 48 bytes for 4 priority levels
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(``CONFIGURE_MAXIMUM_PRIORITY == 3``).
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.. index:: CONFIGURE_MAXIMUM_PROCESSORS
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.. _CONFIGURE_MAXIMUM_PROCESSORS:
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CONFIGURE_MAXIMUM_PROCESSORS
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----------------------------
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CONSTANT:
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``CONFIGURE_MAXIMUM_PROCESSORS``
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DATA TYPE:
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Unsigned integer (``uint32_t``).
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RANGE:
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Positive.
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DEFAULT VALUE:
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The default value is 1.
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DESCRIPTION:
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``CONFIGURE_MAXIMUM_PROCESSORS`` must be set to the maximum number of
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processors an application intends to use. The number of actually available
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processors depends on the hardware and may be less. It is recommended to
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use the smallest value suitable for the application in order to save
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memory. Each processor needs an idle thread and interrupt stack for
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example.
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NOTES:
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If there are more processors available than configured, the rest will be
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ignored. This configuration define is ignored in uniprocessor
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configurations.
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.. index:: CONFIGURE_MAXIMUM_THREAD_NAME_SIZE
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.. index:: maximum thread name size
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.. _CONFIGURE_MAXIMUM_THREAD_NAME_SIZE:
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CONFIGURE_MAXIMUM_THREAD_NAME_SIZE
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----------------------------------
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CONSTANT:
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``CONFIGURE_MAXIMUM_THREAD_NAME_SIZE``
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DATA TYPE:
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Unsigned integer (``size_t``).
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RANGE:
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No restrictions.
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DEFAULT VALUE:
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The default value is 16. This value was chosen for Linux compatibility,
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see
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`PTHREAD_SETNAME_NP(3) <http://man7.org/linux/man-pages/man3/pthread_setname_np.3.html>`_.
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DESCRIPTION:
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This configuration parameter specifies the maximum thread name size
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including the terminating `NUL` character.
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NOTE:
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The size of the thread control block is increased by the maximum thread name
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size. This configuration option is available since RTEMS 5.1.
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.. index:: CONFIGURE_MEMORY_OVERHEAD
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.. _CONFIGURE_MEMORY_OVERHEAD:
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CONFIGURE_MEMORY_OVERHEAD
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-------------------------
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CONSTANT:
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``CONFIGURE_MEMORY_OVERHEAD``
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DATA TYPE:
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Unsigned integer (``size_t``).
|
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RANGE:
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Zero or positive.
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DEFAULT VALUE:
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The default value is 0.
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DESCRIPTION:
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This parameter is set to the number of kilobytes the application wishes to
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add to the requirements calculated by ``<rtems/confdefs.h>``.
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NOTES:
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This configuration parameter should only be used when it is suspected that
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a bug in ``<rtems/confdefs.h>`` has resulted in an underestimation.
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Typically the memory allocation will be too low when an application does
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not account for all message queue buffers or task stacks.
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.. index:: CONFIGURE_MICROSECONDS_PER_TICK
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.. index:: tick quantum
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.. _CONFIGURE_MICROSECONDS_PER_TICK:
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CONFIGURE_MICROSECONDS_PER_TICK
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-------------------------------
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CONSTANT:
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``CONFIGURE_MICROSECONDS_PER_TICK``
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DATA TYPE:
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Unsigned integer (``uint32_t``).
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RANGE:
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Positive.
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DEFAULT VALUE:
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This is not defined by default. When not defined, the clock tick quantum is
|
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configured to be 10,000 microseconds which is ten (10) milliseconds.
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DESCRIPTION:
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This constant is used to specify the length of time between clock ticks.
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When the clock tick quantum value is too low, the system will spend so much
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time processing clock ticks that it does not have processing time available
|
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to perform application work. In this case, the system will become
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unresponsive.
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The lowest practical time quantum varies widely based upon the speed of the
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target hardware and the architectural overhead associated with
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interrupts. In general terms, you do not want to configure it lower than is
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needed for the application.
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The clock tick quantum should be selected such that it all blocking and
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delay times in the application are evenly divisible by it. Otherwise,
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rounding errors will be introduced which may negatively impact the
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application.
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NOTES:
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This configuration parameter has no impact if the Clock Tick Device driver
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is not configured.
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There may be BSP specific limits on the resolution or maximum value of a
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clock tick quantum.
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.. index:: CONFIGURE_MINIMUM_TASK_STACK_SIZE
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.. index:: minimum task stack size
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.. _CONFIGURE_MINIMUM_TASK_STACK_SIZE:
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CONFIGURE_MINIMUM_TASK_STACK_SIZE
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---------------------------------
|
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CONSTANT:
|
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``CONFIGURE_MINIMUM_TASK_STACK_SIZE``
|
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DATA TYPE:
|
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Unsigned integer (``uint32_t``).
|
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RANGE:
|
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Positive.
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DEFAULT VALUE:
|
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The default value is architecture-specific.
|
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DESCRIPTION:
|
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This configuration parameter defines the minimum stack size in bytes for
|
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every user task or thread in the system.
|
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NOTES:
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Adjusting this parameter should be done with caution. Examining the actual
|
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stack usage using the stack checker usage reporting facility is recommended
|
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(see also :ref:`CONFIGURE_STACK_CHECKER_ENABLED <CONFIGURE_STACK_CHECKER_ENABLED>`).
|
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This parameter can be used to lower the minimum from that recommended. This
|
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can be used in low memory systems to reduce memory consumption for
|
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stacks. However, this must be done with caution as it could increase the
|
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possibility of a blown task stack.
|
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|
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This parameter can be used to increase the minimum from that
|
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recommended. This can be used in higher memory systems to reduce the risk
|
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of stack overflow without performing analysis on actual consumption.
|
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By default, this configuration parameter defines also the minimum stack
|
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size of POSIX threads. This can be changed with the
|
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:ref:`CONFIGURE_MINIMUM_POSIX_THREAD_STACK_SIZE <CONFIGURE_MINIMUM_POSIX_THREAD_STACK_SIZE>`
|
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configuration option.
|
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|
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In releases before RTEMS 5.1 the ``CONFIGURE_MINIMUM_TASK_STACK_SIZE`` was
|
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used to define the default value of :ref:`CONFIGURE_INTERRUPT_STACK_SIZE
|
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<CONFIGURE_INTERRUPT_STACK_SIZE>`.
|
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|
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.. index:: CONFIGURE_STACK_CHECKER_ENABLED
|
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|
||||
.. _CONFIGURE_STACK_CHECKER_ENABLED:
|
||||
|
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CONFIGURE_STACK_CHECKER_ENABLED
|
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-------------------------------
|
||||
|
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CONSTANT:
|
||||
``CONFIGURE_STACK_CHECKER_ENABLED``
|
||||
|
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DATA TYPE:
|
||||
Boolean feature macro.
|
||||
|
||||
RANGE:
|
||||
Defined or undefined.
|
||||
|
||||
DEFAULT VALUE:
|
||||
This is not defined by default, and thus stack checking is disabled.
|
||||
|
||||
DESCRIPTION:
|
||||
This configuration parameter is defined when the application wishes to
|
||||
enable run-time stack bounds checking.
|
||||
|
||||
NOTES:
|
||||
In 4.9 and older, this configuration parameter was named ``STACK_CHECKER_ON``.
|
||||
|
||||
This increases the time required to create tasks as well as adding overhead
|
||||
to each context switch.
|
||||
|
||||
.. index:: CONFIGURE_TICKS_PER_TIMESLICE
|
||||
.. index:: ticks per timeslice
|
||||
|
||||
.. _CONFIGURE_TICKS_PER_TIMESLICE:
|
||||
|
||||
CONFIGURE_TICKS_PER_TIMESLICE
|
||||
-----------------------------
|
||||
|
||||
CONSTANT:
|
||||
``CONFIGURE_TICKS_PER_TIMESLICE``
|
||||
|
||||
DATA TYPE:
|
||||
Unsigned integer (``uint32_t``).
|
||||
|
||||
RANGE:
|
||||
Positive.
|
||||
|
||||
DEFAULT VALUE:
|
||||
The default value is 50.
|
||||
|
||||
DESCRIPTION:
|
||||
This configuration parameter specifies the length of the timeslice quantum
|
||||
in ticks for each task.
|
||||
|
||||
NOTES:
|
||||
This configuration parameter has no impact if the Clock Tick Device driver
|
||||
is not configured.
|
||||
|
||||
.. index:: CONFIGURE_UNIFIED_WORK_AREAS
|
||||
.. index:: unified work areas
|
||||
.. index:: separate work areas
|
||||
.. index:: RTEMS Workspace
|
||||
.. index:: C Program Heap
|
||||
|
||||
.. _CONFIGURE_UNIFIED_WORK_AREAS:
|
||||
|
||||
CONFIGURE_UNIFIED_WORK_AREAS
|
||||
----------------------------
|
||||
|
||||
CONSTANT:
|
||||
``CONFIGURE_UNIFIED_WORK_AREAS``
|
||||
|
||||
DATA TYPE:
|
||||
Boolean feature macro.
|
||||
|
||||
RANGE:
|
||||
Defined or undefined.
|
||||
|
||||
DEFAULT VALUE:
|
||||
This is not defined by default, which specifies that the C Program Heap and
|
||||
the RTEMS Workspace will be separate.
|
||||
|
||||
DESCRIPTION:
|
||||
When defined, the C Program Heap and the RTEMS Workspace will be one pool
|
||||
of memory.
|
||||
|
||||
When not defined, there will be separate memory pools for the RTEMS
|
||||
Workspace and C Program Heap.
|
||||
|
||||
NOTES:
|
||||
Having separate pools does have some advantages in the event a task blows a
|
||||
stack or writes outside its memory area. However, in low memory systems the
|
||||
overhead of the two pools plus the potential for unused memory in either
|
||||
pool is very undesirable.
|
||||
|
||||
In high memory environments, this is desirable when you want to use the
|
||||
RTEMS "unlimited" objects option. You will be able to create objects until
|
||||
you run out of all available memory rather then just until you run out of
|
||||
RTEMS Workspace.
|
||||
|
||||
.. _CONFIGURE_UNLIMITED_ALLOCATION_SIZE:
|
||||
|
||||
CONFIGURE_UNLIMITED_ALLOCATION_SIZE
|
||||
-----------------------------------
|
||||
|
||||
CONSTANT:
|
||||
``CONFIGURE_UNLIMITED_ALLOCATION_SIZE``
|
||||
|
||||
DATA TYPE:
|
||||
Unsigned integer (``uint32_t``).
|
||||
|
||||
RANGE:
|
||||
Positive.
|
||||
|
||||
DEFAULT VALUE:
|
||||
If not defined and ``CONFIGURE_UNLIMITED_OBJECTS`` is defined, the default
|
||||
value is eight (8).
|
||||
|
||||
DESCRIPTION:
|
||||
``CONFIGURE_UNLIMITED_ALLOCATION_SIZE`` provides an allocation size to use
|
||||
for ``rtems_resource_unlimited`` when using
|
||||
``CONFIGURE_UNLIMITED_OBJECTS``.
|
||||
|
||||
NOTES:
|
||||
By allowing users to declare all resources as being unlimited the user can
|
||||
avoid identifying and limiting the resources
|
||||
used. ``CONFIGURE_UNLIMITED_OBJECTS`` does not support varying the
|
||||
allocation sizes for different objects; users who want that much control
|
||||
can define the ``rtems_resource_unlimited`` macros themselves.
|
||||
|
||||
.. index:: CONFIGURE_UNLIMITED_OBJECTS
|
||||
|
||||
.. _CONFIGURE_UNLIMITED_OBJECTS:
|
||||
|
||||
CONFIGURE_UNLIMITED_OBJECTS
|
||||
---------------------------
|
||||
|
||||
CONSTANT:
|
||||
``CONFIGURE_UNLIMITED_OBJECTS``
|
||||
|
||||
DATA TYPE:
|
||||
Boolean feature macro.
|
||||
|
||||
RANGE:
|
||||
Defined or undefined.
|
||||
|
||||
DEFAULT VALUE:
|
||||
This is not defined by default.
|
||||
|
||||
DESCRIPTION:
|
||||
``CONFIGURE_UNLIMITED_OBJECTS`` enables ``rtems_resource_unlimited`` mode
|
||||
for Classic API and POSIX API objects that do not already have a specific
|
||||
maximum limit defined.
|
||||
|
||||
NOTES:
|
||||
When using unlimited objects, it is common practice to also specify
|
||||
``CONFIGURE_UNIFIED_WORK_AREAS`` so the system operates with a single pool
|
||||
of memory for both RTEMS and application memory allocations.
|
||||
|
||||
.. index:: CONFIGURE_VERBOSE_SYSTEM_INITIALIZATION
|
||||
|
||||
.. _CONFIGURE_VERBOSE_SYSTEM_INITIALIZATION:
|
||||
|
||||
CONFIGURE_VERBOSE_SYSTEM_INITIALIZATION
|
||||
---------------------------------------
|
||||
|
||||
CONSTANT:
|
||||
``CONFIGURE_VERBOSE_SYSTEM_INITIALIZATION``
|
||||
|
||||
DATA TYPE:
|
||||
Boolean feature macro.
|
||||
|
||||
RANGE:
|
||||
Defined or undefined.
|
||||
|
||||
DEFAULT VALUE:
|
||||
This is not defined by default, and thus the system initialization is
|
||||
quiet.
|
||||
|
||||
DESCRIPTION:
|
||||
This configuration option enables to print some information during system
|
||||
initialization.
|
||||
|
||||
NOTES:
|
||||
You may use this feature to debug system initialization issues. The
|
||||
printk() function is used to print the information.
|
||||
|
||||
.. index:: CONFIGURE_ZERO_WORKSPACE_AUTOMATICALLY
|
||||
.. index:: clear C Program Heap
|
||||
.. index:: clear RTEMS Workspace
|
||||
.. index:: zero C Program Heap
|
||||
.. index:: zero RTEMS Workspace
|
||||
|
||||
.. _CONFIGURE_ZERO_WORKSPACE_AUTOMATICALLY:
|
||||
|
||||
CONFIGURE_ZERO_WORKSPACE_AUTOMATICALLY
|
||||
--------------------------------------
|
||||
|
||||
CONSTANT:
|
||||
``CONFIGURE_ZERO_WORKSPACE_AUTOMATICALLY``
|
||||
|
||||
DATA TYPE:
|
||||
Boolean feature macro.
|
||||
|
||||
RANGE:
|
||||
Defined or undefined.
|
||||
|
||||
DEFAULT VALUE:
|
||||
This is not defined by default. The default is *NOT* to zero out the RTEMS
|
||||
Workspace or C Program Heap.
|
||||
|
||||
DESCRIPTION:
|
||||
This macro indicates whether RTEMS should zero the RTEMS Workspace and C
|
||||
Program Heap as part of its initialization. If defined, the memory regions
|
||||
are zeroed. Otherwise, they are not.
|
||||
|
||||
NOTES:
|
||||
Zeroing memory can add significantly to system boot time. It is not
|
||||
necessary for RTEMS but is often assumed by support libraries. In case
|
||||
:ref:`CONFIGURE_DIRTY_MEMORY` is also defined, then the memory is first
|
||||
dirtied and then zeroed.
|
||||
@ -12,642 +12,7 @@ Configuring a System
|
||||
.. toctree::
|
||||
|
||||
intro
|
||||
|
||||
General System Configuration
|
||||
============================
|
||||
|
||||
This section defines the general system configuration options supported by
|
||||
``<rtems/confdefs.h>``.
|
||||
|
||||
.. index:: CONFIGURE_DIRTY_MEMORY
|
||||
|
||||
.. _CONFIGURE_DIRTY_MEMORY:
|
||||
|
||||
CONFIGURE_DIRTY_MEMORY
|
||||
----------------------
|
||||
|
||||
CONSTANT:
|
||||
``CONFIGURE_DIRTY_MEMORY``
|
||||
|
||||
DATA TYPE:
|
||||
Boolean feature macro.
|
||||
|
||||
RANGE:
|
||||
Defined or undefined.
|
||||
|
||||
DEFAULT VALUE:
|
||||
By default, the memory used by the RTEMS Workspace and the C Program Heap
|
||||
is uninitialized memory.
|
||||
|
||||
DESCRIPTION:
|
||||
This macro indicates whether RTEMS should dirty the memory used by the
|
||||
RTEMS Workspace and the C Program Heap as part of its initialization. If
|
||||
defined, the memory areas are dirtied with a ``0xCF`` byte pattern.
|
||||
Otherwise, they are not.
|
||||
|
||||
NOTES:
|
||||
Dirtying memory can add significantly to system boot time. It may assist in
|
||||
finding code that incorrectly assumes the contents of free memory areas is
|
||||
cleared to zero during system initialization. In case
|
||||
:ref:`CONFIGURE_ZERO_WORKSPACE_AUTOMATICALLY` is also defined, then the
|
||||
memory is first dirtied and then zeroed.
|
||||
|
||||
.. index:: CONFIGURE_EXTRA_TASK_STACKS
|
||||
.. index:: memory for task tasks
|
||||
|
||||
.. _CONFIGURE_EXTRA_TASK_STACKS:
|
||||
|
||||
CONFIGURE_EXTRA_TASK_STACKS
|
||||
---------------------------
|
||||
|
||||
CONSTANT:
|
||||
``CONFIGURE_EXTRA_TASK_STACKS``
|
||||
|
||||
DATA TYPE:
|
||||
Unsigned integer (``size_t``).
|
||||
|
||||
RANGE:
|
||||
Undefined or positive.
|
||||
|
||||
DEFAULT VALUE:
|
||||
The default value is 0.
|
||||
|
||||
DESCRIPTION:
|
||||
This configuration parameter is set to the number of bytes the applications
|
||||
wishes to add to the task stack requirements calculated by
|
||||
``<rtems/confdefs.h>``.
|
||||
|
||||
NOTES:
|
||||
This parameter is very important. If the application creates tasks with
|
||||
stacks larger then the minimum, then that memory is NOT accounted for by
|
||||
``<rtems/confdefs.h>``.
|
||||
|
||||
.. index:: CONFIGURE_INITIAL_EXTENSIONS
|
||||
|
||||
.. _CONFIGURE_INITIAL_EXTENSIONS:
|
||||
|
||||
CONFIGURE_INITIAL_EXTENSIONS
|
||||
----------------------------
|
||||
|
||||
CONSTANT:
|
||||
``CONFIGURE_INITIAL_EXTENSIONS``
|
||||
|
||||
DATA TYPE:
|
||||
List of user extension initializers (``rtems_extensions_table``).
|
||||
|
||||
RANGE:
|
||||
Undefined or a list of one or more user extensions.
|
||||
|
||||
DEFAULT VALUE:
|
||||
This is not defined by default.
|
||||
|
||||
DESCRIPTION:
|
||||
If ``CONFIGURE_INITIAL_EXTENSIONS`` is defined by the application, then
|
||||
this application specific set of initial extensions will be placed in the
|
||||
initial extension table.
|
||||
|
||||
NOTES:
|
||||
None.
|
||||
|
||||
.. index:: CONFIGURE_INTERRUPT_STACK_SIZE
|
||||
.. index:: interrupt stack size
|
||||
|
||||
.. _CONFIGURE_INTERRUPT_STACK_SIZE:
|
||||
|
||||
CONFIGURE_INTERRUPT_STACK_SIZE
|
||||
------------------------------
|
||||
|
||||
CONSTANT:
|
||||
``CONFIGURE_INTERRUPT_STACK_SIZE``
|
||||
|
||||
DATA TYPE:
|
||||
Unsigned integer.
|
||||
|
||||
RANGE:
|
||||
Positive.
|
||||
|
||||
DEFAULT VALUE:
|
||||
The default value is ``BSP_INTERRUPT_STACK_SIZE`` in case it is defined,
|
||||
otherwise the default value is ``CPU_STACK_MINIMUM_SIZE``.
|
||||
|
||||
DESCRIPTION:
|
||||
The ``CONFIGURE_INTERRUPT_STACK_SIZE`` configuration option defines the
|
||||
size of an interrupt stack in bytes.
|
||||
|
||||
NOTES:
|
||||
The interrupt stack size must be aligned according to
|
||||
``CPU_INTERRUPT_STACK_ALIGNMENT``.
|
||||
|
||||
There is one interrupt stack available for each configured processor
|
||||
(:ref:`CONFIGURE_MAXIMUM_PROCESSORS <CONFIGURE_MAXIMUM_PROCESSORS>`). The
|
||||
interrupt stack areas are statically allocated in a special linker section
|
||||
(``.rtemsstack.interrupt``). The placement of this linker section is
|
||||
BSP-specific.
|
||||
|
||||
Some BSPs use the interrupt stack as the initialization stack which is used
|
||||
to perform the sequential system initialization before the multithreading
|
||||
is started.
|
||||
|
||||
The interrupt stacks are covered by the :ref:`stack checker
|
||||
<CONFIGURE_STACK_CHECKER_ENABLED>`. However, using a too small interrupt
|
||||
stack size may still result in undefined behaviour.
|
||||
|
||||
In releases before RTEMS 5.1 the default value was
|
||||
:ref:`CONFIGURE_MINIMUM_TASK_STACK_SIZE
|
||||
<CONFIGURE_MINIMUM_TASK_STACK_SIZE>` instead of ``CPU_STACK_MINIMUM_SIZE``.
|
||||
|
||||
.. index:: CONFIGURE_MAXIMUM_FILE_DESCRIPTORS
|
||||
.. index:: maximum file descriptors
|
||||
|
||||
.. _CONFIGURE_MAXIMUM_FILE_DESCRIPTORS:
|
||||
|
||||
CONFIGURE_MAXIMUM_FILE_DESCRIPTORS
|
||||
----------------------------------
|
||||
|
||||
CONSTANT:
|
||||
``CONFIGURE_MAXIMUM_FILE_DESCRIPTORS``
|
||||
|
||||
DATA TYPE:
|
||||
Unsigned integer (``uint32_t``).
|
||||
|
||||
RANGE:
|
||||
Zero or positive.
|
||||
|
||||
DEFAULT VALUE:
|
||||
If ``CONFIGURE_APPLICATION_NEEDS_CONSOLE_DRIVER`` is defined, then the
|
||||
default value is 3, otherwise the default value is 0. Three file
|
||||
descriptors allows RTEMS to support standard input, output, and error I/O
|
||||
streams on ``/dev/console``.
|
||||
|
||||
DESCRIPTION:
|
||||
This configuration parameter is set to the maximum number of file like
|
||||
objects that can be concurrently open.
|
||||
|
||||
NOTES:
|
||||
None.
|
||||
|
||||
.. index:: CONFIGURE_MAXIMUM_PRIORITY
|
||||
.. index:: maximum priority
|
||||
.. index:: number of priority levels
|
||||
|
||||
.. _CONFIGURE_MAXIMUM_PRIORITY:
|
||||
|
||||
CONFIGURE_MAXIMUM_PRIORITY
|
||||
--------------------------
|
||||
|
||||
CONSTANT:
|
||||
``CONFIGURE_MAXIMUM_PRIORITY``
|
||||
|
||||
DATA TYPE:
|
||||
Unsigned integer (``uint8_t``).
|
||||
|
||||
RANGE:
|
||||
Valid values for this configuration parameter must be one (1) less than
|
||||
than a power of two (2) between 4 and 256 inclusively. In other words,
|
||||
valid values are 3, 7, 31, 63, 127, and 255.
|
||||
|
||||
DEFAULT VALUE:
|
||||
The default value is 255, because RTEMS must support 256 priority levels to
|
||||
be compliant with various standards. These priorities range from zero (0)
|
||||
to 255.
|
||||
|
||||
DESCRIPTION:
|
||||
For the schedulers
|
||||
|
||||
* :ref:`SchedulerPriority`, which is the default in uniprocessor
|
||||
configurations and can be configured through the
|
||||
:ref:`CONFIGURE_SCHEDULER_PRIORITY` configuration option,
|
||||
|
||||
* :ref:`SchedulerSMPPriority` which can be configured through the
|
||||
:ref:`CONFIGURE_SCHEDULER_PRIORITY_SMP` configuration option, and
|
||||
|
||||
* :ref:`SchedulerSMPPriorityAffinity` which can be configured through the
|
||||
:ref:`CONFIGURE_SCHEDULER_PRIORITY_AFFINITY_SMP` configuration option
|
||||
|
||||
this configuration option specifies the maximum numeric priority of any task
|
||||
for these schedulers and one less that the number of priority levels for
|
||||
these schedulers. For all other schedulers provided by RTEMS, this
|
||||
configuration option has no effect.
|
||||
|
||||
NOTES:
|
||||
The numerically greatest priority is the logically lowest priority in the
|
||||
system and will thus be used by the IDLE task.
|
||||
|
||||
Priority zero (0) is reserved for internal use by RTEMS and is not available
|
||||
to applications.
|
||||
|
||||
Reducing the number of priorities through this configuration option reduces
|
||||
the amount of memory allocated by the schedulers listed above. These
|
||||
schedulers use a chain control structure per priority and this structure
|
||||
consists of three pointers. On a 32-bit architecture, the allocated memory
|
||||
is 12 bytes * (``CONFIGURE_MAXIMUM_PRIORITY`` + 1), e.g. 3072 bytes for 256
|
||||
priority levels (default), 48 bytes for 4 priority levels
|
||||
(``CONFIGURE_MAXIMUM_PRIORITY == 3``).
|
||||
|
||||
.. index:: CONFIGURE_MAXIMUM_PROCESSORS
|
||||
|
||||
.. _CONFIGURE_MAXIMUM_PROCESSORS:
|
||||
|
||||
CONFIGURE_MAXIMUM_PROCESSORS
|
||||
----------------------------
|
||||
|
||||
CONSTANT:
|
||||
``CONFIGURE_MAXIMUM_PROCESSORS``
|
||||
|
||||
DATA TYPE:
|
||||
Unsigned integer (``uint32_t``).
|
||||
|
||||
RANGE:
|
||||
Positive.
|
||||
|
||||
DEFAULT VALUE:
|
||||
The default value is 1.
|
||||
|
||||
DESCRIPTION:
|
||||
``CONFIGURE_MAXIMUM_PROCESSORS`` must be set to the maximum number of
|
||||
processors an application intends to use. The number of actually available
|
||||
processors depends on the hardware and may be less. It is recommended to
|
||||
use the smallest value suitable for the application in order to save
|
||||
memory. Each processor needs an idle thread and interrupt stack for
|
||||
example.
|
||||
|
||||
NOTES:
|
||||
If there are more processors available than configured, the rest will be
|
||||
ignored. This configuration define is ignored in uniprocessor
|
||||
configurations.
|
||||
|
||||
.. index:: CONFIGURE_MAXIMUM_THREAD_NAME_SIZE
|
||||
.. index:: maximum thread name size
|
||||
|
||||
.. _CONFIGURE_MAXIMUM_THREAD_NAME_SIZE:
|
||||
|
||||
CONFIGURE_MAXIMUM_THREAD_NAME_SIZE
|
||||
----------------------------------
|
||||
|
||||
CONSTANT:
|
||||
``CONFIGURE_MAXIMUM_THREAD_NAME_SIZE``
|
||||
|
||||
DATA TYPE:
|
||||
Unsigned integer (``size_t``).
|
||||
|
||||
RANGE:
|
||||
No restrictions.
|
||||
|
||||
DEFAULT VALUE:
|
||||
The default value is 16. This value was chosen for Linux compatibility,
|
||||
see
|
||||
`PTHREAD_SETNAME_NP(3) <http://man7.org/linux/man-pages/man3/pthread_setname_np.3.html>`_.
|
||||
|
||||
DESCRIPTION:
|
||||
This configuration parameter specifies the maximum thread name size
|
||||
including the terminating `NUL` character.
|
||||
|
||||
NOTE:
|
||||
The size of the thread control block is increased by the maximum thread name
|
||||
size. This configuration option is available since RTEMS 5.1.
|
||||
|
||||
.. index:: CONFIGURE_MEMORY_OVERHEAD
|
||||
|
||||
.. _CONFIGURE_MEMORY_OVERHEAD:
|
||||
|
||||
CONFIGURE_MEMORY_OVERHEAD
|
||||
-------------------------
|
||||
|
||||
CONSTANT:
|
||||
``CONFIGURE_MEMORY_OVERHEAD``
|
||||
|
||||
DATA TYPE:
|
||||
Unsigned integer (``size_t``).
|
||||
|
||||
RANGE:
|
||||
Zero or positive.
|
||||
|
||||
DEFAULT VALUE:
|
||||
The default value is 0.
|
||||
|
||||
DESCRIPTION:
|
||||
This parameter is set to the number of kilobytes the application wishes to
|
||||
add to the requirements calculated by ``<rtems/confdefs.h>``.
|
||||
|
||||
NOTES:
|
||||
This configuration parameter should only be used when it is suspected that
|
||||
a bug in ``<rtems/confdefs.h>`` has resulted in an underestimation.
|
||||
Typically the memory allocation will be too low when an application does
|
||||
not account for all message queue buffers or task stacks.
|
||||
|
||||
.. index:: CONFIGURE_MICROSECONDS_PER_TICK
|
||||
.. index:: tick quantum
|
||||
|
||||
.. _CONFIGURE_MICROSECONDS_PER_TICK:
|
||||
|
||||
CONFIGURE_MICROSECONDS_PER_TICK
|
||||
-------------------------------
|
||||
|
||||
CONSTANT:
|
||||
``CONFIGURE_MICROSECONDS_PER_TICK``
|
||||
|
||||
DATA TYPE:
|
||||
Unsigned integer (``uint32_t``).
|
||||
|
||||
RANGE:
|
||||
Positive.
|
||||
|
||||
DEFAULT VALUE:
|
||||
This is not defined by default. When not defined, the clock tick quantum is
|
||||
configured to be 10,000 microseconds which is ten (10) milliseconds.
|
||||
|
||||
DESCRIPTION:
|
||||
This constant is used to specify the length of time between clock ticks.
|
||||
|
||||
When the clock tick quantum value is too low, the system will spend so much
|
||||
time processing clock ticks that it does not have processing time available
|
||||
to perform application work. In this case, the system will become
|
||||
unresponsive.
|
||||
|
||||
The lowest practical time quantum varies widely based upon the speed of the
|
||||
target hardware and the architectural overhead associated with
|
||||
interrupts. In general terms, you do not want to configure it lower than is
|
||||
needed for the application.
|
||||
|
||||
The clock tick quantum should be selected such that it all blocking and
|
||||
delay times in the application are evenly divisible by it. Otherwise,
|
||||
rounding errors will be introduced which may negatively impact the
|
||||
application.
|
||||
|
||||
NOTES:
|
||||
This configuration parameter has no impact if the Clock Tick Device driver
|
||||
is not configured.
|
||||
|
||||
There may be BSP specific limits on the resolution or maximum value of a
|
||||
clock tick quantum.
|
||||
|
||||
.. index:: CONFIGURE_MINIMUM_TASK_STACK_SIZE
|
||||
.. index:: minimum task stack size
|
||||
|
||||
.. _CONFIGURE_MINIMUM_TASK_STACK_SIZE:
|
||||
|
||||
CONFIGURE_MINIMUM_TASK_STACK_SIZE
|
||||
---------------------------------
|
||||
|
||||
CONSTANT:
|
||||
``CONFIGURE_MINIMUM_TASK_STACK_SIZE``
|
||||
|
||||
DATA TYPE:
|
||||
Unsigned integer (``uint32_t``).
|
||||
|
||||
RANGE:
|
||||
Positive.
|
||||
|
||||
DEFAULT VALUE:
|
||||
The default value is architecture-specific.
|
||||
|
||||
DESCRIPTION:
|
||||
This configuration parameter defines the minimum stack size in bytes for
|
||||
every user task or thread in the system.
|
||||
|
||||
NOTES:
|
||||
Adjusting this parameter should be done with caution. Examining the actual
|
||||
stack usage using the stack checker usage reporting facility is recommended
|
||||
(see also :ref:`CONFIGURE_STACK_CHECKER_ENABLED <CONFIGURE_STACK_CHECKER_ENABLED>`).
|
||||
|
||||
This parameter can be used to lower the minimum from that recommended. This
|
||||
can be used in low memory systems to reduce memory consumption for
|
||||
stacks. However, this must be done with caution as it could increase the
|
||||
possibility of a blown task stack.
|
||||
|
||||
This parameter can be used to increase the minimum from that
|
||||
recommended. This can be used in higher memory systems to reduce the risk
|
||||
of stack overflow without performing analysis on actual consumption.
|
||||
|
||||
By default, this configuration parameter defines also the minimum stack
|
||||
size of POSIX threads. This can be changed with the
|
||||
:ref:`CONFIGURE_MINIMUM_POSIX_THREAD_STACK_SIZE <CONFIGURE_MINIMUM_POSIX_THREAD_STACK_SIZE>`
|
||||
configuration option.
|
||||
|
||||
In releases before RTEMS 5.1 the ``CONFIGURE_MINIMUM_TASK_STACK_SIZE`` was
|
||||
used to define the default value of :ref:`CONFIGURE_INTERRUPT_STACK_SIZE
|
||||
<CONFIGURE_INTERRUPT_STACK_SIZE>`.
|
||||
|
||||
.. index:: CONFIGURE_STACK_CHECKER_ENABLED
|
||||
|
||||
.. _CONFIGURE_STACK_CHECKER_ENABLED:
|
||||
|
||||
CONFIGURE_STACK_CHECKER_ENABLED
|
||||
-------------------------------
|
||||
|
||||
CONSTANT:
|
||||
``CONFIGURE_STACK_CHECKER_ENABLED``
|
||||
|
||||
DATA TYPE:
|
||||
Boolean feature macro.
|
||||
|
||||
RANGE:
|
||||
Defined or undefined.
|
||||
|
||||
DEFAULT VALUE:
|
||||
This is not defined by default, and thus stack checking is disabled.
|
||||
|
||||
DESCRIPTION:
|
||||
This configuration parameter is defined when the application wishes to
|
||||
enable run-time stack bounds checking.
|
||||
|
||||
NOTES:
|
||||
In 4.9 and older, this configuration parameter was named ``STACK_CHECKER_ON``.
|
||||
|
||||
This increases the time required to create tasks as well as adding overhead
|
||||
to each context switch.
|
||||
|
||||
.. index:: CONFIGURE_TICKS_PER_TIMESLICE
|
||||
.. index:: ticks per timeslice
|
||||
|
||||
.. _CONFIGURE_TICKS_PER_TIMESLICE:
|
||||
|
||||
CONFIGURE_TICKS_PER_TIMESLICE
|
||||
-----------------------------
|
||||
|
||||
CONSTANT:
|
||||
``CONFIGURE_TICKS_PER_TIMESLICE``
|
||||
|
||||
DATA TYPE:
|
||||
Unsigned integer (``uint32_t``).
|
||||
|
||||
RANGE:
|
||||
Positive.
|
||||
|
||||
DEFAULT VALUE:
|
||||
The default value is 50.
|
||||
|
||||
DESCRIPTION:
|
||||
This configuration parameter specifies the length of the timeslice quantum
|
||||
in ticks for each task.
|
||||
|
||||
NOTES:
|
||||
This configuration parameter has no impact if the Clock Tick Device driver
|
||||
is not configured.
|
||||
|
||||
.. index:: CONFIGURE_UNIFIED_WORK_AREAS
|
||||
.. index:: unified work areas
|
||||
.. index:: separate work areas
|
||||
.. index:: RTEMS Workspace
|
||||
.. index:: C Program Heap
|
||||
|
||||
.. _CONFIGURE_UNIFIED_WORK_AREAS:
|
||||
|
||||
CONFIGURE_UNIFIED_WORK_AREAS
|
||||
----------------------------
|
||||
|
||||
CONSTANT:
|
||||
``CONFIGURE_UNIFIED_WORK_AREAS``
|
||||
|
||||
DATA TYPE:
|
||||
Boolean feature macro.
|
||||
|
||||
RANGE:
|
||||
Defined or undefined.
|
||||
|
||||
DEFAULT VALUE:
|
||||
This is not defined by default, which specifies that the C Program Heap and
|
||||
the RTEMS Workspace will be separate.
|
||||
|
||||
DESCRIPTION:
|
||||
When defined, the C Program Heap and the RTEMS Workspace will be one pool
|
||||
of memory.
|
||||
|
||||
When not defined, there will be separate memory pools for the RTEMS
|
||||
Workspace and C Program Heap.
|
||||
|
||||
NOTES:
|
||||
Having separate pools does have some advantages in the event a task blows a
|
||||
stack or writes outside its memory area. However, in low memory systems the
|
||||
overhead of the two pools plus the potential for unused memory in either
|
||||
pool is very undesirable.
|
||||
|
||||
In high memory environments, this is desirable when you want to use the
|
||||
RTEMS "unlimited" objects option. You will be able to create objects until
|
||||
you run out of all available memory rather then just until you run out of
|
||||
RTEMS Workspace.
|
||||
|
||||
.. _CONFIGURE_UNLIMITED_ALLOCATION_SIZE:
|
||||
|
||||
CONFIGURE_UNLIMITED_ALLOCATION_SIZE
|
||||
-----------------------------------
|
||||
|
||||
CONSTANT:
|
||||
``CONFIGURE_UNLIMITED_ALLOCATION_SIZE``
|
||||
|
||||
DATA TYPE:
|
||||
Unsigned integer (``uint32_t``).
|
||||
|
||||
RANGE:
|
||||
Positive.
|
||||
|
||||
DEFAULT VALUE:
|
||||
If not defined and ``CONFIGURE_UNLIMITED_OBJECTS`` is defined, the default
|
||||
value is eight (8).
|
||||
|
||||
DESCRIPTION:
|
||||
``CONFIGURE_UNLIMITED_ALLOCATION_SIZE`` provides an allocation size to use
|
||||
for ``rtems_resource_unlimited`` when using
|
||||
``CONFIGURE_UNLIMITED_OBJECTS``.
|
||||
|
||||
NOTES:
|
||||
By allowing users to declare all resources as being unlimited the user can
|
||||
avoid identifying and limiting the resources
|
||||
used. ``CONFIGURE_UNLIMITED_OBJECTS`` does not support varying the
|
||||
allocation sizes for different objects; users who want that much control
|
||||
can define the ``rtems_resource_unlimited`` macros themselves.
|
||||
|
||||
.. index:: CONFIGURE_UNLIMITED_OBJECTS
|
||||
|
||||
.. _CONFIGURE_UNLIMITED_OBJECTS:
|
||||
|
||||
CONFIGURE_UNLIMITED_OBJECTS
|
||||
---------------------------
|
||||
|
||||
CONSTANT:
|
||||
``CONFIGURE_UNLIMITED_OBJECTS``
|
||||
|
||||
DATA TYPE:
|
||||
Boolean feature macro.
|
||||
|
||||
RANGE:
|
||||
Defined or undefined.
|
||||
|
||||
DEFAULT VALUE:
|
||||
This is not defined by default.
|
||||
|
||||
DESCRIPTION:
|
||||
``CONFIGURE_UNLIMITED_OBJECTS`` enables ``rtems_resource_unlimited`` mode
|
||||
for Classic API and POSIX API objects that do not already have a specific
|
||||
maximum limit defined.
|
||||
|
||||
NOTES:
|
||||
When using unlimited objects, it is common practice to also specify
|
||||
``CONFIGURE_UNIFIED_WORK_AREAS`` so the system operates with a single pool
|
||||
of memory for both RTEMS and application memory allocations.
|
||||
|
||||
.. index:: CONFIGURE_VERBOSE_SYSTEM_INITIALIZATION
|
||||
|
||||
.. _CONFIGURE_VERBOSE_SYSTEM_INITIALIZATION:
|
||||
|
||||
CONFIGURE_VERBOSE_SYSTEM_INITIALIZATION
|
||||
---------------------------------------
|
||||
|
||||
CONSTANT:
|
||||
``CONFIGURE_VERBOSE_SYSTEM_INITIALIZATION``
|
||||
|
||||
DATA TYPE:
|
||||
Boolean feature macro.
|
||||
|
||||
RANGE:
|
||||
Defined or undefined.
|
||||
|
||||
DEFAULT VALUE:
|
||||
This is not defined by default, and thus the system initialization is
|
||||
quiet.
|
||||
|
||||
DESCRIPTION:
|
||||
This configuration option enables to print some information during system
|
||||
initialization.
|
||||
|
||||
NOTES:
|
||||
You may use this feature to debug system initialization issues. The
|
||||
printk() function is used to print the information.
|
||||
|
||||
.. index:: CONFIGURE_ZERO_WORKSPACE_AUTOMATICALLY
|
||||
.. index:: clear C Program Heap
|
||||
.. index:: clear RTEMS Workspace
|
||||
.. index:: zero C Program Heap
|
||||
.. index:: zero RTEMS Workspace
|
||||
|
||||
.. _CONFIGURE_ZERO_WORKSPACE_AUTOMATICALLY:
|
||||
|
||||
CONFIGURE_ZERO_WORKSPACE_AUTOMATICALLY
|
||||
--------------------------------------
|
||||
|
||||
CONSTANT:
|
||||
``CONFIGURE_ZERO_WORKSPACE_AUTOMATICALLY``
|
||||
|
||||
DATA TYPE:
|
||||
Boolean feature macro.
|
||||
|
||||
RANGE:
|
||||
Defined or undefined.
|
||||
|
||||
DEFAULT VALUE:
|
||||
This is not defined by default. The default is *NOT* to zero out the RTEMS
|
||||
Workspace or C Program Heap.
|
||||
|
||||
DESCRIPTION:
|
||||
This macro indicates whether RTEMS should zero the RTEMS Workspace and C
|
||||
Program Heap as part of its initialization. If defined, the memory regions
|
||||
are zeroed. Otherwise, they are not.
|
||||
|
||||
NOTES:
|
||||
Zeroing memory can add significantly to system boot time. It is not
|
||||
necessary for RTEMS but is often assumed by support libraries. In case
|
||||
:ref:`CONFIGURE_DIRTY_MEMORY` is also defined, then the memory is first
|
||||
dirtied and then zeroed.
|
||||
general
|
||||
|
||||
Classic API Configuration
|
||||
=========================
|
||||
|
||||
Loading…
x
Reference in New Issue
Block a user