rt_scheduler.h File Reference

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Detailed Description

Common interface for using an OS-level real-time scheduler.

Note:

This is just an interface, there is no default implementation available, the appropriate one must be selected and linked in.

See also:

rt_scheduler_unix.c

rt_scheduler_rk.c

Definition in file rt_scheduler.h.

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Classes
struct	rts_scheduler_data
struct	rts_schedule
Typedefs
typedef rts_scheduler_data *	rts_scheduler_data_t
typedef void *	rts_schedulable_t
	An opaque reference to scheduler specific data.
typedef rts_schedule *	rts_schedule_t
Enumerations
enum	{ RSDB_RESERVATIONS }
enum	{ RSDF_RESERVATIONS = (1L << RSDB_RESERVATIONS) }
enum	rts_reserve_mode_t { RTS_RSV_MIN, RTS_RSV_SOFT, RTS_RSV_HARD, RTS_RSV_MAX }
	The reservation mode. More...
Functions
int	rts_query_scheduler (rts_scheduler_data_t rsd_out)
	Get information about the underlying scheduler.
int	rts_grab_schedulable (rts_schedulable_t *rs_out, pid_t member, const char *name)
	Grab a reference to a schedulable entity.
int	rts_release_schedulable (rts_schedulable_t rs)
	Release a reference to a schedulable entity.
int	rts_set_schedule (rts_schedulable_t rsa, rts_schedule_t rs)
	Set the real-time schedule for a schedulable.
int	rts_get_schedule (rts_schedulable_t rsa, rts_schedule_t rs_out)
	Get the real-time schedule for a schedulable.
int	rts_clear_schedule (rts_schedulable_t rsa)
	Clear the real-time schedule for a schedulable and return it to a best-effort scheduler.

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Typedef Documentation

typedef void* rts_schedulable_t

An opaque reference to scheduler specific data. The schedulable is used to collect multiple processes under a single schedulable entity. For example, TimeSys Linux schedules a "resource set", which in turn, schedules a process in that set. See also: rts_grab_schedulable rts_release_schedulable Definition at line 73 of file rt_scheduler.h. Referenced by main(), rts_clear_schedule(), rts_get_schedule(), rts_grab_schedulable(), rts_release_schedulable(), and rts_set_schedule().

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Enumeration Type Documentation

anonymous enum

Enumeration values: RSDF_RESERVATIONS  The scheduler supports CPU reservations. Definition at line 37 of file rt_scheduler.h.

enum rts_reserve_mode_t

The reservation mode. Enumeration values: RTS_RSV_MIN  Minimum allowed value. RTS_RSV_SOFT  Soft reservation - use best-effort when needed. RTS_RSV_HARD  Hard reservation - never use best-effort. RTS_RSV_MAX  Maximum allowed value. Definition at line 118 of file rt_scheduler.h.

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Function Documentation

int rts_clear_schedule (  rts_schedulable_t  rsa  )

Clear the real-time schedule for a schedulable and return it to a best-effort scheduler. Parameters: rsa  The schedulable to clear. Returns: Zero on success, otherwise, an errno code. Definition at line 71 of file rt_scheduler_unix.c. References NULL_RESERVE, rk_cpu_reserve_delete(), rts_schedulable_rk::rsr_CPUReserve, rts_schedulable_rk::rsr_ResourceSet, rts_schedulable_rk_t, and rts_schedulable_t. Referenced by StrictPolicyImpl::RedistributeCPU(), WeightedPolicyImpl::RedistributeCPU(), StrictPolicyImpl::RemoveTask(), and WeightedPolicyImpl::RemoveTask().

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int rts_get_schedule (  rts_schedulable_t  rsa, rts_schedule_t  rs_out )

Get the real-time schedule for a schedulable. Parameters: rsa  The schedulable to schedule. rs_out  The new schedule. Returns: Zero on success, otherwise, an errno code. Definition at line 64 of file rt_scheduler_unix.c. References cpu_reserve_attr::compute_time, ensure, NULL_RESERVE, NULL_RESOURCE_SET, cpu_reserve_attr::period, cpu_reserve_attr::reserve_type, rk_cpu_reserve_get_attr(), rts_schedulable_rk::rsr_CPUReserve, rts_schedulable_rk::rsr_ResourceSet, RSV_HARD, RSV_SOFT, RTS_RSV_HARD, RTS_RSV_SOFT, rts_schedulable_rk_t, rts_schedulable_t, and rk_reserve_param::sch_mode.

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int rts_grab_schedulable (  rts_schedulable_t *  rs_out, pid_t  member, const char *  name )

Grab a reference to a schedulable entity. The current semantics of this function are as follows: If necessary, the function must make some effort to "repair" the system state by destroying schedulables that are in a suspicious state. Multiple calls to this function with the same parameters need not return the same pointer, however, their values must be equal. The user must also release the schedulables in the opposite order in which they were grabbed. If the schedulable entity already exists at the OS-level, it should be used instead of creating a new one. If no schedulable entity exists that contains the given process or has the given name, one should be created. Parameters: rs_out  A pointer that should be filled out with the schedulable value. member  A process that is already a member of the schedulable, one that should be added to a newly created schedulable, or -1 if the schedulable should be created by name. name  The name for the schedulable or NULL if one should be made up. Returns: Zero on success, otherwise, an errno code. Definition at line 41 of file rt_scheduler_unix.c. References NULL_RESERVE, NULL_RESOURCE_SET, rk_cpu_reserve_delete(), rk_proc_get_rset(), rk_reserve_t, rk_resource_set_attach_process(), rk_resource_set_create(), rk_resource_set_get_by_name(), rk_resource_set_get_cpu_rsv(), rk_resource_set_get_num_procs(), rts_schedulable_rk::rsr_Flags, rts_schedulable_rk::rsr_ResourceSet, RSRF_OWNER, rts_release_schedulable(), rts_repair_resource_sets(), rts_schedulable_rk_t, and rts_schedulable_t. Referenced by StrictPolicyImpl::AddTask(), WeightedPolicyImpl::AddTask(), and main().

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int rts_query_scheduler (  rts_scheduler_data_t  rsd_out  )

Get information about the underlying scheduler. This function is mostly about making it possible to do run-time adaptation to the scheduler's capabilities. Parameters: rsd_out  A reference to an #rts_scheduler_data object that should be filled in. Definition at line 25 of file rt_scheduler_unix.c. References RSDF_RESERVATIONS. Referenced by main().

int rts_release_schedulable (  rts_schedulable_t  rs  )

Release a reference to a schedulable entity. The current semantics of this function are as follows: If the given schedulable created the OS-level entity, this call should destroy it. If the given schedulable entity was used to set the schedule, this call should clear the schedule. Parameters: rs  The reference from rts_grab_schedulable to release. Returns: Zero on success, otherwise an errno value. Definition at line 50 of file rt_scheduler_unix.c. References NULL_RESERVE, NULL_RESOURCE_SET, rk_cpu_reserve_delete(), rk_resource_set_destroy(), rts_schedulable_rk::rsr_CPUReserve, rts_schedulable_rk::rsr_Flags, rts_schedulable_rk::rsr_ResourceSet, RSRF_OWNER, rts_schedulable_rk_t, and rts_schedulable_t. Referenced by main(), StrictPolicyImpl::RemoveTask(), WeightedPolicyImpl::RemoveTask(), and rts_grab_schedulable().

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int rts_set_schedule (  rts_schedulable_t  rsa, rts_schedule_t  rs )

Set the real-time schedule for a schedulable. Parameters: rsa  The schedulable to schedule. rs  The new schedule. Returns: Zero on success, otherwise, an errno code. Definition at line 57 of file rt_scheduler_unix.c. References ensure, NULL_RESERVE, NULL_RESOURCE_SET, RK_ANY_CPU, rk_cpu_reserve_create(), rk_cpu_reserve_ctl(), rk_resource_set_get_cpu_rsv(), rts_schedulable_rk::rsr_CPUReserve, rts_schedulable_rk::rsr_ResourceSet, RSV_HARD, RSV_SOFT, RTS_RSV_HARD, RTS_RSV_MAX, RTS_RSV_MIN, RTS_RSV_SOFT, rts_schedulable_rk_t, and rts_schedulable_t. Referenced by StrictPolicyImpl::RedistributeCPU(), and WeightedPolicyImpl::RedistributeCPU().

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