11.4. Directives¶

This section details the directives of the Rate-Monotonic Manager. A subsection is dedicated to each of this manager’s directives and lists the calling sequence, parameters, description, return values, and notes of the directive.

11.4.1. rtems_rate_monotonic_create()¶

Creates a period.

CALLING SEQUENCE:

rtems_status_code rtems_rate_monotonic_create( rtems_name name, rtems_id *id );

PARAMETERS:

name: This parameter is the object name of the period.
id: This parameter is the pointer to an rtems_id object. When the directive call is successful, the identifier of the created period will be stored in this object.

DESCRIPTION:

This directive creates a period which resides on the local node. The period has the user-defined object name specified in name The assigned object identifier is returned in id. This identifier is used to access the period with other rate monotonic related directives.

RETURN VALUES:

RTEMS_SUCCESSFUL: The requested operation was successful.
RTEMS_INVALID_NAME: The name parameter was invalid.
RTEMS_TOO_MANY: There was no inactive object available to create a period. The number of periods available to the application is configured through the CONFIGURE_MAXIMUM_PERIODS application configuration option.

NOTES:

The calling task is registered as the owner of the created period. Some directives can be only used by this task for the created period.

For control and maintenance of the period, RTEMS allocates a PCB from the local PCB free pool and initializes it.

CONSTRAINTS:

The following constraints apply to this directive:

The directive may be called from within device driver initialization context.
The directive may be called from within task context.
The directive may obtain and release the object allocator mutex. This may cause the calling task to be preempted.
The number of periods available to the application is configured through the CONFIGURE_MAXIMUM_PERIODS application configuration option.
Where the object class corresponding to the directive is configured to use unlimited objects, the directive may allocate memory from the RTEMS Workspace.

11.4.2. rtems_rate_monotonic_ident()¶

Identifies a period by the object name.

CALLING SEQUENCE:

rtems_status_code rtems_rate_monotonic_ident( rtems_name name, rtems_id *id );

PARAMETERS:

name: This parameter is the object name to look up.
id: This parameter is the pointer to an rtems_id object. When the directive call is successful, the object identifier of an object with the specified name will be stored in this object.

DESCRIPTION:

This directive obtains a period identifier associated with the period name specified in name.

RETURN VALUES:

RTEMS_SUCCESSFUL: The requested operation was successful.
RTEMS_INVALID_ADDRESS: The id parameter was NULL.
RTEMS_INVALID_NAME: The name parameter was 0.
RTEMS_INVALID_NAME: There was no object with the specified name on the local node.

NOTES:

If the period name is not unique, then the period identifier will match the first period with that name in the search order. However, this period identifier is not guaranteed to correspond to the desired period.

The objects are searched from lowest to the highest index. Only the local node is searched.

The period identifier is used with other rate monotonic related directives to access the period.

CONSTRAINTS:

The following constraints apply to this directive:

The directive may be called from within any runtime context.
The directive will not cause the calling task to be preempted.

11.4.3. rtems_rate_monotonic_cancel()¶

Cancels the period.

CALLING SEQUENCE:

rtems_status_code rtems_rate_monotonic_cancel( rtems_id id );

PARAMETERS:

id: This parameter is the rate monotonic period identifier.

DESCRIPTION:

This directive cancels the rate monotonic period specified by id. This period may be reinitiated by the next invocation of rtems_rate_monotonic_period().

RETURN VALUES:

RTEMS_SUCCESSFUL: The requested operation was successful.
RTEMS_INVALID_ID: There was no rate monotonic period associated with the identifier specified by id.
RTEMS_NOT_OWNER_OF_RESOURCE: The rate monotonic period was not created by the calling task.

CONSTRAINTS:

The following constraints apply to this directive:

The directive may be called from within task context.
The directive will not cause the calling task to be preempted.
The directive may be used exclusively by the task which created the associated object.

11.4.4. rtems_rate_monotonic_delete()¶

Deletes the period.

CALLING SEQUENCE:

rtems_status_code rtems_rate_monotonic_delete( rtems_id id );

PARAMETERS:

id: This parameter is the period identifier.

DESCRIPTION:

This directive deletes the period specified by id. If the period is running, it is automatically canceled.

RETURN VALUES:

RTEMS_SUCCESSFUL: The requested operation was successful.
RTEMS_INVALID_ID: There was no period associated with the identifier specified by id.

NOTES:

The PCB for the deleted period is reclaimed by RTEMS.

CONSTRAINTS:

The following constraints apply to this directive:

The directive may be called from within device driver initialization context.
The directive may be called from within task context.
The directive may obtain and release the object allocator mutex. This may cause the calling task to be preempted.
The calling task does not have to be the task that created the object. Any local task that knows the object identifier can delete the object.
Where the object class corresponding to the directive is configured to use unlimited objects, the directive may free memory to the RTEMS Workspace.

11.4.5. rtems_rate_monotonic_period()¶

Concludes the current period and start the next period, or gets the period status.

CALLING SEQUENCE:

rtems_status_code rtems_rate_monotonic_period(
  rtems_id       id,
  rtems_interval length
);

PARAMETERS:

id: This parameter is the rate monotonic period identifier.
length: This parameter is the period length in clock ticks or RTEMS_PERIOD_STATUS to get the period status.

DESCRIPTION:

This directive initiates the rate monotonic period specified by id with a length of period ticks specified by length. If the period is running, then the calling task will block for the remainder of the period before reinitiating the period with the specified period length. If the period was not running (either expired or never initiated), the period is immediately initiated and the directive returns immediately. If the period has expired, the postponed job will be released immediately and the following calls of this directive will release postponed jobs until there is no more deadline miss.

If invoked with a period length of RTEMS_PERIOD_STATUS ticks, the current state of the period will be returned. The directive status indicates the current state of the period. This does not alter the state or period length of the period.

RETURN VALUES:

RTEMS_SUCCESSFUL: The requested operation was successful.
RTEMS_INVALID_ID: There was no rate monotonic period associated with the identifier specified by id.
RTEMS_NOT_OWNER_OF_RESOURCE: The rate monotonic period was not created by the calling task.
RTEMS_NOT_DEFINED: The rate monotonic period has never been initiated (only possible when the length parameter was equal to RTEMS_PERIOD_STATUS).
RTEMS_TIMEOUT: The rate monotonic period has expired.

NOTES:

Resetting the processor usage time of tasks has no impact on the period status and statistics.

CONSTRAINTS:

The following constraints apply to this directive:

The directive may be called from within task context.
The directive may be used exclusively by the task which created the associated object.

11.4.6. rtems_rate_monotonic_get_status()¶

Gets the detailed status of the period.

CALLING SEQUENCE:

rtems_status_code rtems_rate_monotonic_get_status(
  rtems_id                            id,
  rtems_rate_monotonic_period_status *status
);

PARAMETERS:

id: This parameter is the rate monotonic period identifier.
status: This parameter is the pointer to an rtems_rate_monotonic_period_status object. When the directive call is successful, the detailed period status will be stored in this object.

DESCRIPTION:

This directive returns the detailed status of the rate monotonic period specified by id. The detailed status of the period will be returned in the members of the period status object referenced by status:

The owner member is set to the identifier of the owner task of the period.
The state member is set to the current state of the period.
The postponed_jobs_count member is set to the count of jobs which are not released yet.
If the current state of the period is RATE_MONOTONIC_INACTIVE, the since_last_period and executed_since_last_period members will be set to zero. Otherwise, both members will contain time information since the last successful invocation of the rtems_rate_monotonic_period() directive by the owner task. More specifically, the since_last_period member will be set to the time elapsed since the last successful invocation. The executed_since_last_period member will be set to the processor time consumed by the owner task since the last successful invocation.

RETURN VALUES:

RTEMS_SUCCESSFUL: The requested operation was successful.
RTEMS_INVALID_ID: There was no rate monotonic period associated with the identifier specified by id.
RTEMS_INVALID_ADDRESS: The status parameter was NULL.

CONSTRAINTS:

The following constraints apply to this directive:

The directive may be called from within task context.
The directive may be called from within interrupt context.
The directive will not cause the calling task to be preempted.

11.4.7. rtems_rate_monotonic_get_statistics()¶

Gets the statistics of the period.

CALLING SEQUENCE:

rtems_status_code rtems_rate_monotonic_get_statistics(
  rtems_id                                id,
  rtems_rate_monotonic_period_statistics *status
);

PARAMETERS:

id: This parameter is the rate monotonic period identifier.
status: This parameter is the pointer to an rtems_rate_monotonic_period_statistics object. When the directive call is successful, the period statistics will be stored in this object.

DESCRIPTION:

This directive returns the statistics of the rate monotonic period specified by id. The statistics of the period will be returned in the members of the period statistics object referenced by status:

The count member is set to the number of periods executed.
The missed_count member is set to the number of periods missed.
The min_cpu_time member is set to the least amount of processor time used in the period.
The max_cpu_time member is set to the highest amount of processor time used in the period.
The total_cpu_time member is set to the total amount of processor time used in the period.
The min_wall_time member is set to the least amount of CLOCK_MONOTONIC time used in the period.
The max_wall_time member is set to the highest amount of CLOCK_MONOTONIC time used in the period.
The total_wall_time member is set to the total amount of CLOCK_MONOTONIC time used in the period.

RETURN VALUES:

RTEMS_SUCCESSFUL: The requested operation was successful.
RTEMS_INVALID_ID: There was no rate monotonic period associated with the identifier specified by id.
RTEMS_INVALID_ADDRESS: The status parameter was NULL.

CONSTRAINTS:

The following constraints apply to this directive:

The directive may be called from within task context.
The directive may be called from within interrupt context.
The directive will not cause the calling task to be preempted.

11.4.8. rtems_rate_monotonic_reset_statistics()¶

Resets the statistics of the period.

CALLING SEQUENCE:

rtems_status_code rtems_rate_monotonic_reset_statistics( rtems_id id );

PARAMETERS:

id: This parameter is the rate monotonic period identifier.

DESCRIPTION:

This directive resets the statistics of the rate monotonic period specified by id.

RETURN VALUES:

RTEMS_SUCCESSFUL: The requested operation was successful.
RTEMS_INVALID_ID: There was no rate monotonic period associated with the identifier specified by id.

CONSTRAINTS:

The following constraints apply to this directive:

The directive may be called from within task context.
The directive may be called from within interrupt context.
The directive will not cause the calling task to be preempted.

11.4.9. rtems_rate_monotonic_reset_all_statistics()¶

Resets the statistics of all periods.

CALLING SEQUENCE:

void rtems_rate_monotonic_reset_all_statistics( void );

DESCRIPTION:

This directive resets the statistics information associated with all rate monotonic period instances.

CONSTRAINTS:

The following constraints apply to this directive:

The directive may be called from within task context.
The directive may obtain and release the object allocator mutex. This may cause the calling task to be preempted.

11.4.10. rtems_rate_monotonic_report_statistics()¶

Reports the period statistics using the printk() printer.

CALLING SEQUENCE:

void rtems_rate_monotonic_report_statistics( void );

DESCRIPTION:

This directive prints a report on all active periods which have executed at least one period using the printk() printer.

CONSTRAINTS:

The following constraints apply to this directive:

The directive may be called from within task context.
The directive may obtain and release the object allocator mutex. This may cause the calling task to be preempted.

11.4.11. rtems_rate_monotonic_report_statistics_with_plugin()¶

Reports the period statistics using the printer plugin.

CALLING SEQUENCE:

void rtems_rate_monotonic_report_statistics_with_plugin(
  const struct rtems_printer *printer
);

PARAMETERS:

printer: This parameter is the printer plugin to output the report.

DESCRIPTION:

This directive prints a report on all active periods which have executed at least one period using the printer plugin specified by printer.

CONSTRAINTS:

The following constraints apply to this directive:

The directive may be called from within task context.
The directive may obtain and release the object allocator mutex. This may cause the calling task to be preempted.