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/**
@file This file contains the functions and definitions for the core
module.
The file contains all fuinctions and data structures for the core
module of the FSF.
*/
//fsf_core.h
//=================================================================
// FFFFFFIII RRRRR SSTTTTTTT
// FF IIR RR SS
// FF IR SS
// FFFFFF RRRR SSSSST
// FF FI RRR SS
// FF II RRR SS
// FF IIIIIR RS
//
// Basic FSF(FIRST Scheduling Framework) contract management
//================================================================
#include <time.h>
#include <pthread.h>
#include <sys/types.h>
#include <stdbool.h>
#include "fsf_configuration_parameters.h"
#include "fsf_opaque_types.h"
#include "fsf_basic_types.h"
#ifndef _FSF_CORE_H_
#define _FSF_CORE_H_
//////////////////////////////////////////////////////////////////////
// INITIALIZATION SERVICES
//////////////////////////////////////////////////////////////////////
/**
\ingroup coremodule
\defgroup core_init Initialization and utilities
@{
*/
/**
We cannot call any fsf functions before fsf_init. After calling
fsf_init, the main will be executing in the background. Then, it
can do the negotiations, create the threads and, if needed,
activate them via some user-specified synchronization mechanism. It
may also create a contract for itself. The second time this
function is called it fails.
@retval 0 if the system is initialized
@retval FSF_ERR_SYSTEM_ALREADY_INITIALIZED if the function has already
been called before
@retval others It may also return any of the errors that may be
returned by the underlying operating system primitives
required to perform the FSF system start up
*/
int fsf_init();
/**
This function converts an error code to an error message that is
stored in the buffer starting at the location pointed to by
message. The size of this buffer is specified by the size
argument. If the error message is longer than size-1, it is
truncated to that length. Regardless of whether the message is
truncated or not, a final zero character that marks the end of the
string is stored in the buffer. The function fails if the error
code passed does not correspond to any of the fsf error codes.
@retval FSF_ERR_BAD_ARGUMENT error is not a valid value
*/
int fsf_strerror (int error, char *message, size_t size);
/* @} */
/////////////////////////////////////////////////////////////
// CONTRACT PARAMETERS
/////////////////////////////////////////////////////////////
/**
\ingroup coremodule
\defgroup core_contract Contract Creation and Initialization.
These functions are used to create and initialize a contract, and
set its parameters.
*/
/*@{*/
/**
Contract parameters type; it is an opaque type (i.e. the internal
structure of this data type is implementation dependent). The user
can access and modify the parameters of a contract only with the
proper functions, and should never access the data directly.
*/
typedef FSF_CONTRACT_PARAMETERS_T_OPAQUE fsf_contract_parameters_t;
/**
The operation receives a pointer to a contract parameters object
and initializes it, setting it to the default values.
The default values are:
- budget min and max are set to 0;
- period min and max are set to 0;
- the workload is unbounded (FSF_INDETERMINATE);
- the server deadline is equal to the period;
- the budget and deadline overrun are not notified;
- the granularity is set to "continuous";
- the quality and importance are set to the default values;
- the scheduling policy is FSF_NONE.
@param contract the pointer to the contract variable.
@retval FSF_ERR_BAD_ARGUMENT contract is NULL
*/
int fsf_initialize_contract (fsf_contract_parameters_t *contract);
// budget_min => {0,0};
// period_max => {0,0};
// budget_max => {0,0};
// period_min => {0,0};
// workload => DEFAULT_WORKLOAD;
// d_equals_t => DEFAULT_D_EQUALS_T; (false or true)
// deadline => DEFAULT_DEADLINE;
// budget_overrun_sig_notify => 0; (signal number)
// budget_overrun_sig_value => {0, NULL};
// deadline_miss_sig_notify => 0; (signal number)
// deadline_miss_sig_value => {0, NULL};
//
// granularity => DEFAULT_GRANULARITY;
// utilization_set; => size = 0
// quality => DEFAULT_QUALITY; (range 0..100)
// importance => DEFAULT_IMPORTANCE; (range 1..5)
//
// preemption_level => 0; (range 1..2**32-1)
// critical_sections; => size = 0
// sched_policy => DEFAULT_SCHED_POLICY
// (FSF_NONE)
/**
The operation updates the specified contract parameters object by
setting its budget, period, and workload to the specified input
parameters. (Note: the workload is a basic parameter because
bounded tasks are triggered by the scheduler (see the
fsf_schedule_timed_job() operation), while indeterminate tasks are
not; therefore, their programming model is quite different).
@param contract the pointer to the contract object
@param [in] budget_min the minimum budget for the contract
@param [in] period_max the maximum period for the contract
@param [in] workload the kind of workload (can be FSF_BOUNDED or
FSF_INDETERMINATE)
@retval 0 if the operation is succesful
@retval FSF_ERR_BAD_ARGUMENT if any of the pointers is NULL
or if only one of the timespec values is 0, and also if the workload
is not a proper value (FSF_INDETERMINATE or FSF_BOUNDED)
*/
int
fsf_set_contract_basic_parameters
(fsf_contract_parameters_t *contract,
const struct timespec *budget_min,
const struct timespec *period_max,
fsf_workload_t workload);
/**
This operation obtains from the specified contract parameters
object its budget, period, and workload, and copies them to the
places pointed to by the corresponding input parameters.
@param [in] contract the pointer to the contract object
@param[out] budget_min pointer to the variable that will contain
the minimum budget
@param[out] period_max pointer to the variable that will contain the
max_period
@param[out] workload pointer to the variable that will contain the
workload type
@retval FSF_ERR_BAD_ARGUMENT : if contract is NULL
*/
int
fsf_get_contract_basic_parameters
(const fsf_contract_parameters_t *contract,
struct timespec *budget_min,
struct timespec *period_max,
fsf_workload_t *workload);
/**
The operation updates the specified contract parameters
object, specifying the additional parameters requirements of
a contract.
@param contract The pointer to the contract object
@param [in] d_equals_t It is a boolean value, set to true (1) if the
we want to specify a deadline different from the period
for the contract.
@param [in] deadline If the previous parameter is set to true,
this parameter should be set to NULL_DEADLINE. Otherwise,
it contains the desired deadline value.
@param [in] budget_overrun_sig_notify contains the number of posix signal
that must be raised if the budget of the server is overrun.
If the value of this parameter is NULL_SIGNAL, no signal will
be raised.
@param [in] budget_overrun_sig_value contains the value that will be
passed to the signal "catcher" when the signal is raised.
This parameters is not used if the budget_overrun_sig_notify
parameters is set to NULL_SIGNAL.
@param [in] deadline_miss_sig_notify contains the number of posix
signal that must be raised if the deadline of the server
is missed. If the value of this parameter is NULL_SIGNAL,
no signal is raised.
@param [in] deadline_miss_sig_value contains the value that will be
passed to the signal "catcher" when the signal is raised.
This parameters is not used if the budget_overrun_sig_notify
parameters is set to NULL_SIGNAL
@retval 0 if the operation is succesful
@retval FSF_BAD_ARGUMENT if contract is NULL or
(d_equals_t is true and deadline is not FSF_NULL_DEADLINE) or
(budget_overrun_sig_notify is not a valid signal) or
(deadline_miss_sig_notify is not a valid signal) or
(d_equals_t is false but (deadline is FSF_NULL_DEADLINE or its value
is grater than the contracts maximum period))
@see sigexplanation
*/
int
fsf_set_contract_timing_requirements
(fsf_contract_parameters_t *contract,
bool d_equals_t,
const struct timespec *deadline,
int budget_overrun_sig_notify,
union sigval budget_overrun_sig_value,
int deadline_miss_sig_notify,
union sigval deadline_miss_sig_value);
/**
The operation obtains the corresponding input parameters from the
specified contract parameters object. If d_equals_t is true, the
deadline will not be updated.
@retval FSF_ERR_BAD_ARGUMENT if contract is NULL
@see fsf_set_contract_timing_requirements
*/
int
fsf_get_contract_timing_requirements
(const fsf_contract_parameters_t *contract,
bool *d_equals_t,
struct timespec *deadline,
int *budget_overrun_sig_notify,
union sigval *budget_overrun_sig_value,
int *deadline_miss_sig_notify,
union sigval *deadline_miss_sig_value);
/*@}*/
//////////////////////////////////////////////////////////////////
// SYNCHRONIZATION OBJECTS
//////////////////////////////////////////////////////////////////
/**
\ingroup coremodule
\defgroup core_synch Synchronization objects
These objects are used to synchronize threads belonging to bounded
workload servers.
In the future we may add a broadcast operation that would signal a
group of synchronization objects. We have not included a broadcast
service in this version because it can be easily created by the
user by signalling individual synchronization objects inside a
loop.
Notice that for synchronization objects there is no naming service
like in shared objects because tasks that use synchronization are
not developed independently, as they are closely coupled.
*/
/*@{*/
/**
An abstract synchronization object is defined by the application.
This object can be used by an application to wait for an event to
arrive by invoking the fsf_schedule_triggered_job() operation. It
can also be used to signal the event either causing a waiting
server to wake up, or the event to be queued if no server is
waiting for it.
*/
typedef FSF_SYNCH_OBJ_HANDLE_T_OPAQUE fsf_synch_obj_handle_t;
/**
This operation creates and initializes a synchronization object
variable managed by the scheduler, and returns a handle to it in
the variable pointed to by synch_handle.
@param[out] synch_handle pointer to the variable that will contain
the handle to the newly created synchronization object
@retval 0 if the operation is succesful
@retval FSF_ERR_BAD_ARGUMENT if synch_handle is 0
@retval FSF_ERR_TOO_MANY_SYNCH_OBJS if the number of synchronization
objects in the system has already exceeded the maximum
@retval FSF_ERR_NOT_SCHEDULED_CALLING_THREAD if the calling thread is not
scheduled under the FSF
@retval FSF_ERR_INVALID_SCHEDULER_REPLY the scheduler is wrong
or not running
*/
int
fsf_create_synch_obj
(fsf_synch_obj_handle_t *synch_handle);
/**
This function sends a notification to the synchronization object
specified as parameter. If there is at least one server waiting on
the synchronization object, the corresponding thread is unblocked,
and the server rules for budget recharging apply.
If more than one server is waiting, just one of them is woken.
However, which one is woken is implementation dependent.
If no thread is waiting on the synchronization object, the
notification is queued.
@param [in] synch_handle the handle of the synchronization object to
notify.
@retval 0 if the operation is completed succesfully
@retval FSF_ERR_BAD_ARGUMENT if synch_handle is 0
@retval FSF_ERR_INVALID_SYNCH_OBJ_HANDLE if the handle is not valid
@retval FSF_ERR_NOT_SCHEDULED_CALLING_THREAD if the calling thread
is not scheduled under the FSF
@retval FSF_ERR_INVALID_SCHEDULER_REPLY the scheduler is wrong or
not running
@retval FSF_ERR_TOO_MANY_EVENTS_IN_SYNCH_OBJ if the number of
events stored in the synchronization object reaches the
maximum defined in the configuration parameter header file
@see fsf_schedule_triggered_job, fsf_timed_schedule_triggered_job
*/
int
fsf_signal_synch_obj
(fsf_synch_obj_handle_t synch_handle);
/**
This operation destroys the synchronization object (created by a
previous call to fsf_create_synch_obj) that is referenced by the
synch_handle variable. After calling this operation, the
synch_handle variable can not be used until it is initialized again
by a call to fsf_create_synch_obj.
@param synch_handle the handle to the synchronization object
to be destroyed
@retval 0 if the operation is succesful
@retval FSF_ERR_INVALID_SYNCH_OBJ_HANDLE is the handle is not valid
@retval FSF_ERR_BAD_ARGUMENT if synch_handle is 0
@retval FSF_ERR_INVALID_SYNCH_OBJ_HANDLE if the handle is not valid
@retval FSF_ERR_NOT_SCHEDULED_CALLING_THREAD if the calling thread is not
scheduled under the FSF
@retval FSF_ERR_INVALID_SCHEDULER_REPLY the scheduler is wrong or
not running
@see fsf_create_synch_obj
*/
int
fsf_destroy_synch_obj
(fsf_synch_obj_handle_t synch_handle);
////////////////////////////////////////////////////
// SCHEDULING BOUNDED WORKLOADS
////////////////////////////////////////////////////
/**
This operation is invoked by threads associated with bounded
workload servers to indicate that a job has been completed (and
that the scheduler may reassign the unused capacity of the current
job to other servers). It is also invoked when the first job of
such threads has to be scheduled.
As an effect, the system will make the current server's budget zero
for the remainder of the server's period, and will not replenish
the budget until the specified absolute time. At that time, all
pending budget replenishments (if any) are made effective. Once the
server has a positive budget and the scheduler schedules the
calling thread again, the call returns and at that time, except for
those parameters equal to NULL pointers, the system reports the
current period and budget for the current job, whether the deadline
of the previous job was missed or not, and whether the budget of
the previous job was overrun or not.
In a system with hierarchical scheduling, since this call makes the
budget zero, the other threads in the same server are not run. As
mentioned abobe, only when the call finishes the budget may be
replenished.
@param [in] abs_time absolute time at which the budget will be
replenished
@param [out] next_budget upon return of this function, the variable
pointed by this function will be equal to
the current server budget. If this parameter is
set to NULL, no action is taken.
@param [out] next_period upon return of this function, the variable
pointed by this function will be equal to
the current server period. If this parameter is
set to NULL, no action is taken.
@param [out] was_deadline_missed upon return of this function, the
variable pointed by this function will be
equal to true if the previous server deadline
was missed, to false otherwise. If this
parameter is set to NULL, no action is
taken.
@param [out] was_budget_overran upon return of this function, the
variable pointed by this function will be
equal to true if the previous server budget was
overrun, to false otherwise. If this
parameter is set to NULL, no action is
taken.
@retval 0 if the operation is succesful
@retval FSF_ERR_INVALID_SCHEDULER_REPLY the scheduler is wrong or
not running
@retval FSF_ERR_INTERNAL_ERROR erroneous binding or malfunction of the FSF
main scheduler
@retval FSF_ERR_NOT_SCHEDULED_CALLING_THREAD if the calling thread is
not scheduled under the FSF
@retval FSF_ERR_UNBOUND if the calling thread does not have a valid
server bound to it
@retval FSF_ERR_BAD_ARGUMENT if the workload of the server is not
FSF_BOUNDED
@sa fsf_schedule_triggered_job, fsf_timed_schedule_triggered_job
*/
int
fsf_schedule_timed_job
(const struct timespec *abs_time,
struct timespec *next_budget,
struct timespec *next_period,
bool *was_deadline_missed,
bool *was_budget_overran);
/**
This operation is invoked by threads associated with bounded
workload servers to indicate that a job has been completed (and
that the scheduler may reassign the unused capacity of the current
job to other servers). It is also invoked when the first job of
such threads has to be scheduled. If the specified synchronization
object has events queued, one of them is dequeued; otherwise the
server will wait upon the specified synchronization object, the
server's budget will be made zero for the remainder of the server's
period, and the implementation will not replenish the budget until
the specified synchronization object is signalled.
At that time, all pending budget replenishments (if any) are made
effective. Once the server has a positive budget and the scheduler
schedules the calling thread again, the call returns and at that
time, except for those parameters equal to NULL pointers, the
system reports the current period and budget for the current job,
whether the deadline of the previous job was missed or not, and
whether the budget of the previous job was overrun or not.
In a system with hierarchical scheduling, since this call makes the
budget zero, the other threads in the same server are not run. As
mentioned above, only when the call finishes the budget may be
replenished.
@param [in] synch_handle handle of the synchronization object
@param [out] next_budget upon return of this function, the variable
pointed by this function will be equal
to the current server budget. If this
parameter is set to NULL, no action is
taken.
@param [out] next_period upon return of this function, the variable
pointed by this function will be equal to
the current server period. If this parameter is
set to NULL, no action is taken.
@param [out] was_deadline_missed upon return of this function, the
variable pointed by this function will be
equal to true if the previous server deadline
was missed, to false otherwise. If this
parameter is set to NULL, no action is
taken.
@param [out] was_budget_overran upon return of this function, the
variable pointed by this function will be
equal to true if the previous server budget was
overrun, to false otherwise. If this
parameter is set to NULL, no action is
taken.
@retval 0 if the operation is succesful
@retval FSF_ERR_INVALID_SYNCH_OBJ_HANDLE if the handle is not valid
@retval FSF_ERR_INVALID_SCHEDULER_REPLY the scheduler is wrong or not
running
@retval FSF_ERR_INTERNAL_ERROR erroneous binding or malfunction of
the FSF main scheduler
@retval FSF_ERR_NOT_SCHEDULED_CALLING_THREAD if the calling thread
is not scheduled under the FSF
@retval FSF_ERR_UNBOUND if the calling thread does not have
a valid server bound to it
@retval FSF_ERR_BAD_ARGUMENT if the workload of the server is not
FSF_BOUNDED or the synch_handle given is not valid
@sa fsf_schedule_triggered_job, fsf_schedule_timed_job
*/
int
fsf_schedule_triggered_job
(fsf_synch_obj_handle_t synch_handle,
struct timespec *next_budget,
struct timespec *next_period,
bool *was_deadline_missed,
bool *was_budget_overran);
/**
This call is the same as fsf_schedule_triggered_job, but with an
absolute timeout. The timed_out argument, indicates whether the
function returned because of a timeout or not
@retval FSF_ERR_INVALID_SCHEDULER_REPLY the scheduler is wrong or
not running
@retval FSF_ERR_INTERNAL_ERROR erroneous binding or malfunction
of the FSF main scheduler
@retval FSF_ERR_NOT_SCHEDULED_CALLING_THREAD if the calling thread is
not scheduled under the FSF
@retval FSF_ERR_UNBOUND if the calling thread does not have a valid
server bound to it
@retval FSF_ERR_BAD_ARGUMENT if the workload of the server is not
FSF_BOUNDED, the synch_handle given is not valid or the abs_timeout
argument is NULL or its value is in the past
@see fsf_schedule_triggered_job
*/
int
fsf_timed_schedule_triggered_job
(fsf_synch_obj_handle_t synch_handle,
const struct timespec *abs_timeout,
bool *timed_out,
struct timespec *next_budget,
struct timespec *next_period,
bool *was_deadline_missed,
bool *was_budget_overran);
/*@}*/
///////////////////////////////////////////////////////////////////
// CONTRACT NEGOCIATION OPERATIONS
///////////////////////////////////////////////////////////////////
/**
\ingroup coremodule
\defgroup core_negotiate Negotiate contract functions
The following functions are used to create servers for a contract
parameters specification and also to assign one or more threads to
a server.
*/
/*@{*/
/**
Server Id type, that identifies a server created to manage a given
contract
*/
typedef int fsf_server_id_t; // => 0
/**
The type references a function that may become a thread's
code
*/
typedef void * (*fsf_thread_code_t) (void *);
/**
The operation negotiates a contract for a new server. If the
on-line admission test is enabled it determines whether the
contract can be admitted or not based on the current contracts
established in the system. Then it creates the server and
recalculates all necessary parameters for the contracts already
present in the system.
This is a potentially blocking operation; it returns when the
system has either rejected the contract, or admitted it and made it
effective. It returns zero and places the server identification
number in the location pointed to by the server input parameter if
accepted, or an error if rejected. No thread is bound to the newly
created server, which will be idle until a thread is bound to
it. This operation can only be executed by threads that are already
bound to an active server and therefore are being scheduled by the
fsf scheduler.
@param [in] contract pointer to the contract
@param [out] server server id
@retval 0 if the call is succesful
@retval FSF_ERR_INVALID_SCHEDULER_REPLY the scheduler is wrong or not
running
@retval FSF_ERR_INTERNAL_ERROR erroneous binding or malfunction of the FSF
main scheduler
@retval FSF_ERR_NOT_SCHEDULED_CALLING_THREAD
if the calling thread is not scheduled
under the FSF
@retval FSF_ERR_BAD_ARGUMENT if the contract or server arguments
are NULL
*/
int
fsf_negotiate_contract
(const fsf_contract_parameters_t *contract,
fsf_server_id_t *server);
/**
This operation negotiates a contract for a new server, creates a
thread and binds it to the server. If the contract is accepted, the
operation creates a thread with the arguments thread, attr,
thread_code and arg as they are defined for the pthread_create()
POSIX function call, and attaches it to the fsf scheduler. Then, it
binds the created thread to the new server. It returns zero and
puts the server identification number in the location pointed to by
the server input parameter.
The attr parameter is overwritten as necessary to introduce the
adequate scheduling attributes, according to the information given
in the contract.
The server is created with the FSF_NONE scheduling policy, which
means no hierarchical scheduling, and only one thread per server,
except for the case of background tasks (see below)
If the contract is rejected, the thread is not created and the
corresponding error is returned.
@param [in] contract pointer to the contract
@param [out] server server id
@param [out] thread thread id
@param [in] attr threads attributes
@param [in] thread_code pointer to the function that implements
the thread
@param [in] arg arguments for the thread
@retval FSF_ERR_BAD_ARGUMENT if the contract or server arguments are NULL
@retval FSF_ERR_CONTRACT_REJECTED if the contract is rejected
@retval others it may also return all the errors that may be returned
by the pthread_create()POSIX function call
*/
int
fsf_negotiate_contract_for_new_thread
(const fsf_contract_parameters_t *contract,
fsf_server_id_t *server,
pthread_t *thread,
pthread_attr_t *attr,
fsf_thread_code_t thread_code,
void *arg);
/**
This operation negotiates a contract for a new server, and binds
the calling thread to it. If the contract is accepted it returns
zero and copies the server identification number in the location
pointed to by the server input parameter. If it is rejected, an
error is returned.
The server is created with the FSF_NONE scheduling policy, which
means no hierarchical scheduling, and only one thread per server,
except for the case of background tasks (see below)
Implementation dependent issue: In order to allow the usage of
application defined schedulers, the calling thread must not have
the SCHED_APP scheduling policy and at the same time be attached to
an application scheduler different than the fsf scheduler; in such
case, an error is returned. After a successful call the calling
thread will have the SCHED_APP scheduling policy and will be
attached to the fsf scheduler.
@param [in] contract pointer to the contract
@param [out] server id
@retval 0 if the contract negotation is succesful
@retval FSF_ERR_UNKNOWN_APPSCHEDULED_THREAD if the thread is attached to
an application defined scheduler different than the fsf scheduler
@retval FSF_ERR_BAD_ARGUMENT if the contract or server arguments
are NULL
@retval FSF_ERR_CONTRACT_REJECTED if the contract is rejected.
*/
int
fsf_negotiate_contract_for_myself
(const fsf_contract_parameters_t *contract,
fsf_server_id_t *server);
/**
This operation associates a thread with a server, which means that
it starts consuming the server's budget and is executed according
to the contract established for that server. If the thread is
already bound to another server, and error is returned.
It fails if the server's policy is different than FSF_NONE, or if
there is already a thread bound to this server
Implementation dependent issue: In order to allow the usage of
application defined schedulers, the given thread must not have the
scheduling policy SCHED_APP and at the same time be attached to an
application scheduler different than the fsf scheduler.
@param [in] server id
@param [in] thread id
@retval FSF_ERR_INTERNAL_ERROR erroneous binding or malfunction
of the FSF main scheduler
@retval FSF_ERR_UNKNOWN_APPSCHEDULED_THREAD if the thread is attached to
an application defined scheduler different than the fsf scheduler
@retval FSF_ERR_BAD_ARGUMENT if the server value does not complain with the
expected format or valid range or the given thread does not exist
@retval FSF_ERR_NOT_CONTRACTED_SERVER if the referenced server
is not valid
@retval FSF_ERR_ALREADY_BOUND if the thread is already bound to
another server.
*/
int
fsf_bind_thread_to_server
(fsf_server_id_t server,
pthread_t thread);
/**
This operation unbinds a thread from a server. Since threads with
no server associated are not allow to execute, they remain in a
dormant state until they are either eliminated or bound again.
If the thread is inside a critical section the effects of this call
are deferred until the critical section is ended
Implementation dependent issue: in the implementation with an
application scheduler, the thread is still attached to the fsf
scheduler, but suspended.
@param [in] thread thread id
@retval 0 if the operation is succesful
@retval FSF_ERR_INTERNAL_ERROR erroneous binding or malfunction of the FSF
main scheduler
@retval FSF_ERR_BAD_ARGUMENT if the given thread does not exist
@retval FSF_ERR_NOT_SCHEDULED_THREAD if the given thread is not scheduled
under the FSF
@retval FSF_ERR_UNKNOWN_APPSCHEDULED_THREAD if the thread is attached to
an application defined scheduler different than the fsf scheduler
@retval FSF_ERR_NOT_BOUND if the given thread does not have a valid
server bound to it
*/
int
fsf_unbind_thread_from_server (pthread_t thread);
/**
This operation stores the Id of the server associated with the
specified thread in the variable pointed to by server. It returns
an error if the thread does not exist, it is not under the control
of the scheduling framework, or is not bound.
@param [in] thread thread id
@param [out] server server
@retval 0 if the operation is succesful
@return FSF_ERR_NOT_SCHEDULED_THREAD if the given thread is not scheduled
under the FSF
@return FSF_ERR_UNBOUND if the given thread does not have a valid
server bound to it
@return FSF_ERR_BAD_ARGUMENT if the given thread does not exist or the
server argument is NULL
*/
int
fsf_get_server
(pthread_t thread,
fsf_server_id_t *server);
/**
This operation stores the contract parameters currently associated
with the specified server in the variable pointed to by
contract. It returns an error if the server id is incorrect.
@param [in] server server id
@param [out] contract pointer to the contract structure
@retval 0 if the operation is succesful
@retval FSF_ERR_BAD_ARGUMENT if the contract argument is
NULL or the value of the server argument is not in range
@retval FSF_ERR_NOT_SCHEDULED_CALLING_THREAD if the calling thread is not
scheduled under the FSF
@retval FSF_ERR_INVALID_SCHEDULER_REPLY the scheduler is wrong or
not running
@retval FSF_ERR_NOT_CONTRACTED_SERVER if the server of the calling thread
has been cancelled or it is not valid
*/
int
fsf_get_contract
(fsf_server_id_t server,
fsf_contract_parameters_t *contract);
/**
The operation eliminates the specified server
and recalculates all necessary parameters for the contracts
remaining in the system. This is a potentially blocking operation;
it returns when the system has made the changes effective.
@param [in] server server id
@retval 0 if the operation is succesful
@retval FSF_ERR_BAD_ARGUMENT if the value of server is not in range
@retval FSF_ERR_NOT_SCHEDULED_CALLING_THREAD if the calling thread is not
scheduled under the FSF
@retval FSF_ERR_INVALID_SCHEDULER_REPLY the scheduler is wrong or not
running
@retval FSF_ERR_NOT_CONTRACTED_SERVER if the server of the calling thread
has been cancelled or it is not valid
*/
int
fsf_cancel_contract (fsf_server_id_t server);
/**
The operation renegotiates a contract for an existing server. If
the on-line admission test is enabled it determines whether the
contract can be admitted or not based on the current contracts
established in the system. If it cannot be admitted, the old
contract remains in effect and an error is returned. If it can be
admitted, it recalculates all necessary parameters for the
contracts already present in the system anr returns zero. This is a
potentially blocking operation; it returns when the system has
either rejected the new contract, or admitted it and made it
effective.
@param [in] new_contract a pointer to the new contract
@param [in] server server id
@retval 0 if the operation is succesful
@retval FSF_ERR_BAD_ARGUMENT if the new_contract argument is NULL or the
value of the server argument is not in range
@retval FSF_ERR_NOT_SCHEDULED_CALLING_THREAD if the calling thread is not
scheduled under the FSF
@retval FSF_ERR_INVALID_SCHEDULER_REPLY the scheduler is wrong or not
running
@retval FSF_ERR_NOT_CONTRACTED_SERVER if the server of the calling thread
has been cancelled or it is not valid
*/
int
fsf_renegotiate_contract
(const fsf_contract_parameters_t *new_contract,
fsf_server_id_t server);
/**
The operation enqueues a renegotiate operation for an existing
server, and returns immediately. The renegotiate operation is
performed asynchronously and the calling thread may continue
executing normally. Of course, wheter the operation is performed
immediately or not depends on the relative priority of the service
thread and the calling thread, on the scheduler used, etc.
When the renegotiation is completed, if the on-line admission test
is enabled it determines whether the contract can be admitted or
not based on the current contracts established in the system. If it
cannot be admitted, the old contract remains in effect. If it can
be admitted, it recalculates all necessary parameters for the
contracts already present in the system. When the operation is
completed, notification is made to the caller, if requested, via a
signal. The status of the operation (in progress, admitted,
rejected) can be checked with the get_renegotiation_status
operation. The argument sig_notify can be NULL_SIGNAL (no
notification), or any POSIX signal; and in this case sig_value is
to be sent with the signal.
@param [in] new_contract pointer to the new contract to be negotiated
@param [in] server server id
@param [in] sig_notify NULL (no signal) or any POSIX signal
@param [in] sig_value a sigval structure that contains values to be
passed to the signal handler. Valid only if sig_notify
is different from NULL.
@retval 0 if the call is succesful
@retval FSF_ERR_BAD_ARGUMENT if the new_contract argument is NULL, the
value of the server argument is not in range or sig_notify is
neither NULL nor a valid POSIX signal
@retval FSF_ERR_NOT_SCHEDULED_CALLING_THREAD if the calling thread is not
scheduled under the FSF
@retval FSF_ERR_INVALID_SCHEDULER_REPLY the scheduler is wrong or not
running
@retval FSF_ERR_NOT_CONTRACTED_SERVER if the server of the calling thread
has been cancelled or it is not valid
*/
int
fsf_request_contract_renegotiation
(const fsf_contract_parameters_t *new_contract,
fsf_server_id_t server,
int sig_notify,
union sigval sig_value);
/**
Possible values returned by fsf_get_renegotiation_status
*/
typedef enum {FSF_IN_PROGRESS,
FSF_REJECTED,
FSF_ADMITTED}
fsf_renegotiation_status_t;
/**
The operation reports on the status of the last renegotiation
operation enqueued for the specified server. It is callable even
after notification of the completion of such operation, if
requested.
@param [in] server server id
@param [out] renegotiation_status the status of the renegotiation;
@retval 0 if succesful completion;
@retval FSF_ERR_BAD_ARGUMENT if the renegotiation_status argument is
NULL or the value of the server argument is not in range
@retval FSF_ERR_NOT_SCHEDULED_CALLING_THREAD if the calling thread is not
scheduled under the FSF
@retval FSF_ERR_INVALID_SCHEDULER_REPLY the scheduler is wrong or not
running
@retval FSF_ERR_NOT_CONTRACTED_SERVER if the server of the calling thread
has been cancelled or it is not valid
*/
int
fsf_get_renegotiation_status
(fsf_server_id_t server,
fsf_renegotiation_status_t *renegotiation_status);
//Data types
/// List of contracts to negotiate
typedef struct {
int size;
fsf_contract_parameters_t* contracts[FSF_MAX_N_SERVERS];
} fsf_contracts_group_t;
/// List of servers to cancel
typedef struct {
int size;
fsf_server_id_t servers[FSF_MAX_N_SERVERS];
} fsf_servers_group_t;
/**
This operation analizes the schedulability of the context that
results from negitiating the contracts specified in the
contracts_up list and cacelling the contracts referenced by the
servers_down list. If the overall negotiation is successful, a new
server will be created for each of the elements of the contracts_up
group, the servers in servers_down will be cancelled, the list of
new server ids will be returned in the variable pointed to by
servers_up, and the variable pointed to by accepted will be made
true. Otherwise, this variable will be made false, and no other
effect will take place. The function returns the corresponding
error code if any of the contracts is not correct or any of the
server is is not valid.
@param [in] contracts_up list of contracts to negotiate
@param [in] servers_down list of contracts to be canceled
@param [out] servers_up list of server ids that have been created, they are
given in the same order as the contract_up list of contracts;
@param [out] accepted if the operation is succesful;
@retval 0 if succesful completion;
@retval FSF_ERR_INVALID_SCHEDULER_REPLY the scheduler is wrong or
not running
@retval FSF_ERR_INTERNAL_ERROR erroneous binding or malfunction of the FSF
main scheduler
@retval FSF_ERR_NOT_SCHEDULED_CALLING_THREAD if the calling thread is
not scheduled under the FSF
@retval FSF_ERR_BAD_ARGUMENT if any of the servers_up or accepted arguments
is NULL, if the contracts_up and servers_down arguments are both NULL,
or any of them has erroneous size or its elements are NULL or not in the
valid range respectively
*/
int
fsf_negotiate_group
(const fsf_contracts_group_t *contracts_up,
const fsf_servers_group_t *servers_down,
fsf_servers_group_t *servers_up,
bool *accepted);
/*@}*/
////////////////////////////////////////////////////
// OBTAINING INFORMATION FROM THE SCHEDULER
////////////////////////////////////////////////////
/**
\ingroup coremodule
\defgroup core_sched_info Obtaining information from the scheduler.
This group of function is used to get informations from the
scheduler, like execution time of a task, remaining budget of a
server, etc.
@{
*/
/**
Returns true if the system is configured with the on-line admission
test enabled, or false otherwise.
*/
bool
fsf_is_admission_test_enabled();
/**
This function stores the current execution time spent by the
threads bound to the specified server in the variable pointed to by
cpu_time.
@param [in] server server id
@param [out] cpu_time pointer to a timespec structure that will contain
the cpu time consumed by the threads that are bound to the
specific server, since its creation.
@retval 0 if succesful completion
@retval FSF_ERR_BAD_ARGUMENT if the value of the server argument is
not in range or cpu_time is NULL
@retval FSF_ERR_NOT_SCHEDULED_CALLING_THREAD if the calling thread is not
scheduled under the FSF
@retval FSF_ERR_INVALID_SCHEDULER_REPLY the scheduler is wrong or
not running
@retval FSF_ERR_NOT_CONTRACTED_SERVER if the server of the calling thread
has been cancelled or it is not valid
*/
int
fsf_get_cpu_time
(fsf_server_id_t server,
struct timespec *cpu_time);
/**
This function stores in the variable pointed to by budget the
remaining execution-time budget associated with the specified
server.
@param [in] server server id
@param [out] budget pointer to a timespec structure that will
contain the remaining budget
@retval 0 if succesful completion
@retval FSF_ERR_BAD_ARGUMENT if the value of the server argument is
not in range or budget is NULL
@retval FSF_ERR_NOT_SCHEDULED_CALLING_THREAD if the calling thread is not
scheduled under the FSF
@retval FSF_ERR_INVALID_SCHEDULER_REPLY the scheduler is wrong or
not running
@retval FSF_ERR_NOT_CONTRACTED_SERVER if the server of the calling thread
has been cancelled or it is not valid
*/
int
fsf_get_remaining_budget
(fsf_server_id_t server,
struct timespec *budget);
/**
This function stores in the variables pointed to by budget and
period, the execution-time budget and the period respectively
associated with the specified server. If any of these pointers is
NULL, the corresponding information is not stored.
@param [in] server server id
@param [out] budget budget available for the current server instance
@param [out] period period available for the current server instance
@retval 0 if succesful completion
@retval FSF_ERR_BAD_ARGUMENT if the value of the server argument is
not in range, budget is NULL or period is NULL
@retval FSF_ERR_NOT_SCHEDULED_CALLING_THREAD if the calling thread is not
scheduled under the FSF
@retval FSF_ERR_INVALID_SCHEDULER_REPLY the scheduler is wrong or not
running
@retval FSF_ERR_NOT_CONTRACTED_SERVER if the server of the calling thread
has been cancelled or it is not valid
*/
int
fsf_get_budget_and_period
(fsf_server_id_t server,
struct timespec *budget,
struct timespec *period);
/* @} */
/////////////////////////////////////////////////////////////////////
// SERVICE THREAD TUNING
/////////////////////////////////////////////////////////////////////
/**
\ingroup coremodule
\defgroup core_service_thread Service Thread
These functions are to the initialization and tuning of the service
thread.
Implementation dependency: in the fixed priority implementation of
fsf, the default priority is lower than the priority of any server,
but higher than the background. According to the
implementation-dependent module the priority is adjustable by means
of a function that changes its preemption level.
@{
*/
/**
This function allows the application to change the period and
budget of the service thread that makes the
negotiations. Increasing the utilization of this thread makes the
negotiations faster, but introduces additional load in the system
that may decrease the bandwidth available for the servers. For this
call, the system will make a schedulability analysis to determine
if the new situation is acceptable or not. This is reported back in
the variable pointed to by accepted. If the new service thread data
is accepted, the system will reassign budgets and periods to the
servers according to the new bandwidth available, in the same way
as it does for a regular contract negotiation.
When its budget is exhausted, the service thread may run in the
background.
The service thread starts with a default budget and period that are
configurable.
@param [in] budget budget for the service thread
@param [in] period for the service thread
@param [out] accepted true is the change has been accepted
@retval 0 is the operation is succesful
@retval FSF_ERR_BAD_ARGUMENT if any of the pointer arguments is NULL or
the budget value is greater than the period value
@retval FSF_ERR_NOT_SCHEDULED_CALLING_THREAD if the calling thread is not
scheduled under the FSF
@retval FSF_ERR_INVALID_SCHEDULER_REPLY the scheduler is wrong or
not running
@retval FSF_ERR_NOT_CONTRACTED_SERVER if the server of the calling thread
has been cancelled or it is not valid
*/
int
fsf_set_service_thread_data
(const struct timespec *budget,
const struct timespec *period,
bool *accepted);
/**
this function returns in the variables pointed by budget and
period, respectively, the current budget and period of the service
thread.
@param [out] budget current budget of the service thread
@param [out] period current period of the service thread
@retval FSF_ERR_BAD_ARGUMENT if any of the pointer arguments is NULL
@retval FSF_ERR_NOT_SCHEDULED_CALLING_THREAD if the calling thread is not
scheduled under the FSF
@retval FSF_ERR_INVALID_SCHEDULER_REPLY the scheduler is wrong
or not running
@retval FSF_ERR_NOT_CONTRACTED_SERVER if the server of the calling thread
has been cancelled or it is not valid
*/
int
fsf_get_service_thread_data
(struct timespec *budget,
struct timespec *period);
/* @} */
#endif // _FSF_CORE_H_