RTEMS 6.1-rc1
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Files | |
file | scheduler.h |
This header file contains interfaces to define a scheduler configuration for an application. | |
Macros | |
#define | CONFIGURE_CBS_MAXIMUM_SERVERS |
This configuration option is an integer define. More... | |
#define | CONFIGURE_MAXIMUM_PRIORITY |
This configuration option is an integer define. More... | |
#define | CONFIGURE_SCHEDULER_ASSIGNMENTS |
This configuration option is an initializer define. More... | |
#define | CONFIGURE_SCHEDULER_CBS |
This configuration option is a boolean feature define. More... | |
#define | CONFIGURE_SCHEDULER_EDF |
This configuration option is a boolean feature define. More... | |
#define | CONFIGURE_SCHEDULER_EDF_SMP |
This configuration option is a boolean feature define. More... | |
#define | CONFIGURE_SCHEDULER_NAME |
This configuration option is an integer define. More... | |
#define | CONFIGURE_SCHEDULER_PRIORITY |
This configuration option is a boolean feature define. More... | |
#define | CONFIGURE_SCHEDULER_PRIORITY_AFFINITY_SMP |
This configuration option is a boolean feature define. More... | |
#define | CONFIGURE_SCHEDULER_PRIORITY_SMP |
This configuration option is a boolean feature define. More... | |
#define | CONFIGURE_SCHEDULER_SIMPLE |
This configuration option is a boolean feature define. More... | |
#define | CONFIGURE_SCHEDULER_SIMPLE_SMP |
This configuration option is a boolean feature define. More... | |
#define | CONFIGURE_SCHEDULER_STRONG_APA |
This configuration option is a boolean feature define. More... | |
#define | CONFIGURE_SCHEDULER_TABLE_ENTRIES |
This configuration option is an initializer define. More... | |
#define | CONFIGURE_SCHEDULER_USER |
This configuration option is a boolean feature define. More... | |
#define | RTEMS_SCHEDULER_CBS(name) static Scheduler_EDF_Context SCHEDULER_CBS_CONTEXT_NAME( name ) |
Defines a CBS Scheduler instantiation. More... | |
#define | RTEMS_SCHEDULER_TABLE_CBS(name, obj_name) |
Defines a CBS Scheduler entry for the scheduler table. More... | |
#define | RTEMS_SCHEDULER_EDF(name) static Scheduler_EDF_Context SCHEDULER_EDF_CONTEXT_NAME( name ) |
Defines an EDF Scheduler instantiation. More... | |
#define | RTEMS_SCHEDULER_TABLE_EDF(name, obj_name) |
Defines an EDF Scheduler entry for the scheduler table. More... | |
#define | RTEMS_SCHEDULER_EDF_SMP(name) |
Defines an EDF SMP Scheduler instantiation. More... | |
#define | RTEMS_SCHEDULER_TABLE_EDF_SMP(name, obj_name) |
Defines an EDF SMP Scheduler entry for the scheduler table. More... | |
#define | RTEMS_SCHEDULER_PRIORITY(name, prio_count) |
Defines a Deterministic Priority Scheduler instantiation. More... | |
#define | RTEMS_SCHEDULER_TABLE_PRIORITY(name, obj_name) |
Defines a Deterministic Priority Scheduler entry for the scheduler table. More... | |
#define | RTEMS_SCHEDULER_PRIORITY_AFFINITY_SMP(name, prio_count) |
Defines a Arbitrary Processor Affinity Priority SMP Scheduler instantiation. More... | |
#define | RTEMS_SCHEDULER_TABLE_PRIORITY_AFFINITY_SMP(name, obj_name) |
Defines a Arbitrary Processor Affinity Priority SMP Scheduler entry for the scheduler table. More... | |
#define | RTEMS_SCHEDULER_PRIORITY_SMP(name, prio_count) |
Defines a Deterministic Priority SMP Scheduler instantiation. More... | |
#define | RTEMS_SCHEDULER_TABLE_PRIORITY_SMP(name, obj_name) |
Defines a Deterministic Priority SMP Scheduler entry for the scheduler table. More... | |
#define | RTEMS_SCHEDULER_STRONG_APA(name, prio_count) |
Defines a Strong APA Scheduler instantiation. More... | |
#define | RTEMS_SCHEDULER_TABLE_STRONG_APA(name, obj_name) |
Defines a Strong APA Scheduler entry for the scheduler table. More... | |
#define | RTEMS_SCHEDULER_SIMPLE(name) |
Defines a Simple Scheduler instantiation. More... | |
#define | RTEMS_SCHEDULER_TABLE_SIMPLE(name, obj_name) |
Defines a Simple Scheduler entry for the scheduler table. More... | |
#define | RTEMS_SCHEDULER_SIMPLE_SMP(name) |
Defines a Simple SMP Scheduler instantiation. More... | |
#define | RTEMS_SCHEDULER_TABLE_SIMPLE_SMP(name, obj_name) |
Defines a Simple SMP Scheduler entry for the scheduler table. More... | |
This section describes configuration options related to selecting a scheduling algorithm for an application. A scheduler configuration is optional and only necessary in very specific circumstances. A normal application configuration does not need any of the configuration options described in this section.
By default, the Deterministic Priority Scheduler algorithm is used in uniprocessor configurations. In case SMP is enabled and the configured maximum processors (CONFIGURE_MAXIMUM_PROCESSORS) is greater than one, then the Earliest Deadline First SMP Scheduler is selected as the default scheduler algorithm.
For the schedulers provided by RTEMS (see Scheduling Concepts), the configuration is straightforward. All that is required is to define the configuration option which specifies which scheduler you want for in your application.
The pluggable scheduler interface also enables the user to provide their own scheduling algorithm. If you choose to do this, you must define multiple configuration option.
#define CONFIGURE_CBS_MAXIMUM_SERVERS |
This configuration option is an integer define.
The value of this configuration option defines the maximum number Constant Bandwidth Servers that can be concurrently active.
The following constraints apply to this configuration option:
#define CONFIGURE_MAXIMUM_PRIORITY |
This configuration option is an integer define.
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.
The numerically greatest priority is the logically lowest priority in the system and will thus be used by the IDLE task.
Priority zero 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
).
The default value is 255, because RTEMS shall support 256 priority levels to be compliant with various standards. These priorities range from 0 to 255.
#define CONFIGURE_SCHEDULER_ASSIGNMENTS |
This configuration option is an initializer define.
The value of this configuration option is used to initialize the initial scheduler to processor assignments.
The following constraints apply to this configuration option:
The value of the configuration option shall be a list of the following macros:
RTEMS_SCHEDULER_ASSIGN( scheduler_index, attributes )
RTEMS_SCHEDULER_ASSIGN_NO_SCHEDULER
The scheduler_index
macro parameter shall be a valid index of the scheduler table defined by the CONFIGURE_SCHEDULER_TABLE_ENTRIES configuration option.
The attributes
macro parameter shall be set to exactly one of the following constants:
RTEMS_SCHEDULER_ASSIGN_PROCESSOR_MANDATORY
RTEMS_SCHEDULER_ASSIGN_PROCESSOR_OPTIONAL
Where the system was built with SMP support enabled, this configuration option is evaluated, otherwise it is ignored.
This is an advanced configuration option, see Clustered Scheduler Configuration.
#define CONFIGURE_SCHEDULER_CBS |
This configuration option is a boolean feature define.
In case this configuration option is defined, then the Constant Bandwidth Server Scheduling (CBS) algorithm is made available to the application.
This scheduler configuration option is an advanced configuration option. Think twice before you use it.
In case no explicit Clustered Scheduler Configuration is present, then it is used as the scheduler for exactly one processor.
#define CONFIGURE_SCHEDULER_EDF |
This configuration option is a boolean feature define.
In case this configuration option is defined, then the Earliest Deadline First Scheduler algorithm is made available to the application.
This scheduler configuration option is an advanced configuration option. Think twice before you use it.
In case no explicit Clustered Scheduler Configuration is present, then it is used as the scheduler for exactly one processor.
#define CONFIGURE_SCHEDULER_EDF_SMP |
This configuration option is a boolean feature define.
In case this configuration option is defined, then the Earliest Deadline First SMP Scheduler algorithm is made available to the application.
This scheduler configuration option is an advanced configuration option. Think twice before you use it.
This scheduler algorithm is only available when RTEMS is built with SMP support enabled.
In case no explicit Clustered Scheduler Configuration is present, then it is used as the scheduler for up to 32 processors.
This scheduler algorithm is the default in SMP configurations if CONFIGURE_MAXIMUM_PROCESSORS is greater than one.
#define CONFIGURE_SCHEDULER_NAME |
This configuration option is an integer define.
The value of this configuration option defines the name of the default scheduler.
The default value is
"MEDF"
for the Earliest Deadline First SMP Scheduler,"MPA "
for the Arbitrary Processor Affinity Priority SMP Scheduler,"MPD "
for the Deterministic Priority SMP Scheduler,"MPS "
for the Simple Priority SMP Scheduler,"UCBS"
for the Constant Bandwidth Server Scheduling (CBS),"UEDF"
for the Earliest Deadline First Scheduler,"UPD "
for the Deterministic Priority Scheduler, and"UPS "
for the Simple Priority Scheduler. This scheduler configuration option is an advanced configuration option. Think twice before you use it.
Schedulers can be identified via rtems_scheduler_ident().
Use rtems_build_name() to define the scheduler name.
#define CONFIGURE_SCHEDULER_PRIORITY |
This configuration option is a boolean feature define.
In case this configuration option is defined, then the Deterministic Priority Scheduler algorithm is made available to the application.
This scheduler configuration option is an advanced configuration option. Think twice before you use it.
In case no explicit Clustered Scheduler Configuration is present, then it is used as the scheduler for exactly one processor.
This scheduler algorithm is the default when CONFIGURE_MAXIMUM_PROCESSORS is exactly one.
The memory allocated for this scheduler depends on the CONFIGURE_MAXIMUM_PRIORITY configuration option.
#define CONFIGURE_SCHEDULER_PRIORITY_AFFINITY_SMP |
This configuration option is a boolean feature define.
In case this configuration option is defined, then the Arbitrary Processor Affinity Priority SMP Scheduler algorithm is made available to the application.
This scheduler configuration option is an advanced configuration option. Think twice before you use it.
This scheduler algorithm is only available when RTEMS is built with SMP support enabled.
In case no explicit Clustered Scheduler Configuration is present, then it is used as the scheduler for up to 32 processors.
The memory allocated for this scheduler depends on the CONFIGURE_MAXIMUM_PRIORITY configuration option.
#define CONFIGURE_SCHEDULER_PRIORITY_SMP |
This configuration option is a boolean feature define.
In case this configuration option is defined, then the Deterministic Priority SMP Scheduler algorithm is made available to the application.
This scheduler configuration option is an advanced configuration option. Think twice before you use it.
This scheduler algorithm is only available when RTEMS is built with SMP support enabled.
In case no explicit Clustered Scheduler Configuration is present, then it is used as the scheduler for up to 32 processors.
The memory allocated for this scheduler depends on the CONFIGURE_MAXIMUM_PRIORITY configuration option.
#define CONFIGURE_SCHEDULER_SIMPLE |
This configuration option is a boolean feature define.
In case this configuration option is defined, then the Simple Priority Scheduler algorithm is made available to the application.
This scheduler configuration option is an advanced configuration option. Think twice before you use it.
In case no explicit Clustered Scheduler Configuration is present, then it is used as the scheduler for exactly one processor.
#define CONFIGURE_SCHEDULER_SIMPLE_SMP |
This configuration option is a boolean feature define.
In case this configuration option is defined, then the Simple Priority SMP Scheduler algorithm is made available to the application.
This scheduler configuration option is an advanced configuration option. Think twice before you use it.
This scheduler algorithm is only available when RTEMS is built with SMP support enabled.
In case no explicit Clustered Scheduler Configuration is present, then it is used as the scheduler for up to 32 processors.
#define CONFIGURE_SCHEDULER_STRONG_APA |
This configuration option is a boolean feature define.
In case this configuration option is defined, then the Strong APA algorithm is made available to the application.
This scheduler configuration option is an advanced configuration option. Think twice before you use it.
This scheduler algorithm is only available when RTEMS is built with SMP support enabled.
This scheduler algorithm is not correctly implemented. Do not use it.
#define CONFIGURE_SCHEDULER_TABLE_ENTRIES |
This configuration option is an initializer define.
The value of this configuration option is used to initialize the table of configured schedulers.
The following constraints apply to this configuration option:
The value of the configuration option shall be a list of the following macros:
RTEMS_SCHEDULER_TABLE_CBS( name, obj_name )
RTEMS_SCHEDULER_TABLE_EDF( name, obj_name )
RTEMS_SCHEDULER_TABLE_EDF_SMP( name, obj_name )
RTEMS_SCHEDULER_TABLE_PRIORITY_AFFINITY_SMP( name, obj_name )
RTEMS_SCHEDULER_TABLE_PRIORITY( name, obj_name )
RTEMS_SCHEDULER_TABLE_PRIORITY_SMP( name, obj_name )
RTEMS_SCHEDULER_TABLE_SIMPLE( name, obj_name )
RTEMS_SCHEDULER_TABLE_SIMPLE_SMP( name, obj_name )
RTEMS_SCHEDULER_TABLE_STRONG_APA( name, obj_name )
The name
macro parameter shall be the name associated with the scheduler data structures, see Clustered Scheduler Configuration.
The obj_name
macro parameter shall be the scheduler object name. It is recommended to define the scheduler object name through rtems_build_name().
Schedulers registered in the scheduler table by this configuration option are available to the application. The scheduler table entry index defines the index of the scheduler.
This is an advanced configuration option, see Clustered Scheduler Configuration.
#define CONFIGURE_SCHEDULER_USER |
This configuration option is a boolean feature define.
In case this configuration option is defined, then the user shall provide a scheduler algorithm to the application.
This scheduler configuration option is an advanced configuration option. Think twice before you use it.
RTEMS allows the application to provide its own task/thread scheduling algorithm. In order to do this, one shall define CONFIGURE_SCHEDULER_USER
to indicate the application provides its own scheduling algorithm. If CONFIGURE_SCHEDULER_USER
is defined then the following additional macros shall be defined:
CONFIGURE_SCHEDULER
shall be defined to a static definition of the scheduler data structures of the user scheduler.CONFIGURE_SCHEDULER_TABLE_ENTRIES
shall be defined to a scheduler table entry initializer for the user scheduler.CONFIGURE_SCHEDULER_USER_PER_THREAD
shall be defined to the type of the per-thread information of the user scheduler.At this time, the mechanics and requirements for writing a new scheduler are evolving and not fully documented. It is recommended that you look at the existing Deterministic Priority Scheduler in cpukit/score/src/schedulerpriority*.c
for guidance. For guidance on the configuration macros, please examine cpukit/include/rtems/confdefs/scheduler.h
for how these are defined for the Deterministic Priority Scheduler.
#define RTEMS_SCHEDULER_CBS | ( | name | ) | static Scheduler_EDF_Context SCHEDULER_CBS_CONTEXT_NAME( name ) |
Defines a CBS Scheduler instantiation.
name | is the scheduler instantiation name. |
#define RTEMS_SCHEDULER_EDF | ( | name | ) | static Scheduler_EDF_Context SCHEDULER_EDF_CONTEXT_NAME( name ) |
Defines an EDF Scheduler instantiation.
name | is the scheduler instantiation name. |
#define RTEMS_SCHEDULER_EDF_SMP | ( | name | ) |
Defines an EDF SMP Scheduler instantiation.
name | is the scheduler instantiation name. |
#define RTEMS_SCHEDULER_PRIORITY | ( | name, | |
prio_count | |||
) |
Defines a Deterministic Priority Scheduler instantiation.
name | is the scheduler instantiation name. |
prio_count | is the count of supported priority levels. |
#define RTEMS_SCHEDULER_PRIORITY_AFFINITY_SMP | ( | name, | |
prio_count | |||
) |
Defines a Arbitrary Processor Affinity Priority SMP Scheduler instantiation.
name | is the scheduler instantiation name. |
prio_count | is the count of supported priority levels. |
#define RTEMS_SCHEDULER_PRIORITY_SMP | ( | name, | |
prio_count | |||
) |
Defines a Deterministic Priority SMP Scheduler instantiation.
name | is the scheduler instantiation name. |
prio_count | is the count of supported priority levels. |
#define RTEMS_SCHEDULER_SIMPLE | ( | name | ) |
Defines a Simple Scheduler instantiation.
name | is the scheduler instantiation name. |
#define RTEMS_SCHEDULER_SIMPLE_SMP | ( | name | ) |
Defines a Simple SMP Scheduler instantiation.
name | is the scheduler instantiation name. |
#define RTEMS_SCHEDULER_STRONG_APA | ( | name, | |
prio_count | |||
) |
Defines a Strong APA Scheduler instantiation.
name | is the scheduler instantiation name. |
#define RTEMS_SCHEDULER_TABLE_CBS | ( | name, | |
obj_name | |||
) |
Defines a CBS Scheduler entry for the scheduler table.
Use this macro to define an entry for the CONFIGURE_SCHEDULER_TABLE_ENTRIES application configuration option.
name | is the scheduler instantiation name. |
name | is the scheduler object name. |
#define RTEMS_SCHEDULER_TABLE_EDF | ( | name, | |
obj_name | |||
) |
Defines an EDF Scheduler entry for the scheduler table.
Use this macro to define an entry for the CONFIGURE_SCHEDULER_TABLE_ENTRIES application configuration option.
name | is the scheduler instantiation name. |
name | is the scheduler object name. |
#define RTEMS_SCHEDULER_TABLE_EDF_SMP | ( | name, | |
obj_name | |||
) |
Defines an EDF SMP Scheduler entry for the scheduler table.
Use this macro to define an entry for the CONFIGURE_SCHEDULER_TABLE_ENTRIES application configuration option.
name | is the scheduler instantiation name. |
name | is the scheduler object name. |
#define RTEMS_SCHEDULER_TABLE_PRIORITY | ( | name, | |
obj_name | |||
) |
Defines a Deterministic Priority Scheduler entry for the scheduler table.
Use this macro to define an entry for the CONFIGURE_SCHEDULER_TABLE_ENTRIES application configuration option.
name | is the scheduler instantiation name. |
name | is the scheduler object name. |
#define RTEMS_SCHEDULER_TABLE_PRIORITY_AFFINITY_SMP | ( | name, | |
obj_name | |||
) |
Defines a Arbitrary Processor Affinity Priority SMP Scheduler entry for the scheduler table.
Use this macro to define an entry for the CONFIGURE_SCHEDULER_TABLE_ENTRIES application configuration option.
name | is the scheduler instantiation name. |
name | is the scheduler object name. |
#define RTEMS_SCHEDULER_TABLE_PRIORITY_SMP | ( | name, | |
obj_name | |||
) |
Defines a Deterministic Priority SMP Scheduler entry for the scheduler table.
Use this macro to define an entry for the CONFIGURE_SCHEDULER_TABLE_ENTRIES application configuration option.
name | is the scheduler instantiation name. |
name | is the scheduler object name. |
#define RTEMS_SCHEDULER_TABLE_SIMPLE | ( | name, | |
obj_name | |||
) |
Defines a Simple Scheduler entry for the scheduler table.
Use this macro to define an entry for the CONFIGURE_SCHEDULER_TABLE_ENTRIES application configuration option.
name | is the scheduler instantiation name. |
name | is the scheduler object name. |
#define RTEMS_SCHEDULER_TABLE_SIMPLE_SMP | ( | name, | |
obj_name | |||
) |
Defines a Simple SMP Scheduler entry for the scheduler table.
Use this macro to define an entry for the CONFIGURE_SCHEDULER_TABLE_ENTRIES application configuration option.
name | is the scheduler instantiation name. |
name | is the scheduler object name. |
#define RTEMS_SCHEDULER_TABLE_STRONG_APA | ( | name, | |
obj_name | |||
) |
Defines a Strong APA Scheduler entry for the scheduler table.
Use this macro to define an entry for the CONFIGURE_SCHEDULER_TABLE_ENTRIES application configuration option.
name | is the scheduler instantiation name. |
name | is the scheduler object name. |