SimGrid
3.18
Versatile Simulation of Distributed Systems
|
Task structure of MSG (msg_task_t) and associated functions.
Since most scheduling algorithms rely on a concept of task that can be either computed locally or transferred on another processor, it seems to be the right level of abstraction for our purposes.
See Task Actions to see how to put the tasks in action.
A task may then be defined by a computing amount, a message size and some private data.
Macros | |
#define | MSG_TASK_UNINITIALIZED NULL |
Default value for an uninitialized msg_task_t. More... | |
Typedefs | |
typedef struct msg_task * | msg_task_t |
Task datatype. More... | |
Functions | |
msg_task_t | MSG_task_create (const char *name, double flop_amount, double message_size, void *data) |
Creates a new msg_task_t. More... | |
msg_task_t | MSG_parallel_task_create (const char *name, int host_nb, const msg_host_t *host_list, double *flops_amount, double *bytes_amount, void *data) |
Creates a new msg_task_t (a parallel one....). More... | |
void * | MSG_task_get_data (msg_task_t task) |
Return the user data of a msg_task_t. More... | |
void | MSG_task_set_data (msg_task_t task, void *data) |
Sets the user data of a msg_task_t. More... | |
void | MSG_task_set_copy_callback (void(*callback)(msg_task_t task, msg_process_t sender, msg_process_t receiver)) |
Sets a function to be called when a task has just been copied. More... | |
msg_process_t | MSG_task_get_sender (msg_task_t task) |
Return the sender of a msg_task_t. More... | |
msg_host_t | MSG_task_get_source (msg_task_t task) |
Return the source of a msg_task_t. More... | |
const char * | MSG_task_get_name (msg_task_t task) |
Return the name of a msg_task_t. More... | |
void | MSG_task_set_name (msg_task_t task, const char *name) |
Sets the name of a msg_task_t. More... | |
msg_error_t | MSG_task_destroy (msg_task_t task) |
Destroy a msg_task_t. More... | |
double | MSG_task_get_remaining_work_ratio (msg_task_t task) |
Returns a value in ]0,1[ that represent the task remaining work to do: starts at 1 and goes to 0. More... | |
double | MSG_task_get_flops_amount (msg_task_t task) |
Returns the amount of flops that remain to be computed. More... | |
void | MSG_task_set_flops_amount (msg_task_t task, double flops_amount) |
set the computation amount needed to process a task msg_task_t. More... | |
void | MSG_task_set_bytes_amount (msg_task_t task, double data_size) |
set the amount data attached with a task msg_task_t. More... | |
double | MSG_task_get_remaining_communication (msg_task_t task) |
Returns the total amount received by a task msg_task_t. More... | |
double | MSG_task_get_bytes_amount (msg_task_t task) |
Returns the size of the data attached to a task msg_task_t. More... | |
void | MSG_task_set_priority (msg_task_t task, double priority) |
Changes the priority of a computation task. More... | |
void | MSG_task_set_bound (msg_task_t task, double bound) |
Changes the maximum CPU utilization of a computation task. More... | |
#define MSG_TASK_UNINITIALIZED NULL |
Default value for an uninitialized msg_task_t.
typedef struct msg_task* msg_task_t |
Task datatype.
A task may then be defined by a computing amount, a message size and some private data.
msg_task_t MSG_task_create | ( | const char * | name, |
double | flop_amount, | ||
double | message_size, | ||
void * | data | ||
) |
Creates a new msg_task_t.
A constructor for msg_task_t taking four arguments and returning the corresponding object.
name | a name for the object. It is for user-level information and can be nullptr. |
flop_amount | a value of the processing amount (in flop) needed to process this new task. If 0, then it cannot be executed with MSG_task_execute(). This value has to be >=0. |
message_size | a value of the amount of data (in bytes) needed to transfer this new task. If 0, then it cannot be transfered with MSG_task_send() and MSG_task_recv(). This value has to be >=0. |
data | a pointer to any data may want to attach to the new object. It is for user-level information and can be nullptr. It can be retrieved with the function MSG_task_get_data. |
msg_task_t MSG_parallel_task_create | ( | const char * | name, |
int | host_nb, | ||
const msg_host_t * | host_list, | ||
double * | flops_amount, | ||
double * | bytes_amount, | ||
void * | data | ||
) |
Creates a new msg_task_t (a parallel one....).
A constructor for msg_task_t taking six arguments and returning the corresponding object.
name | a name for the object. It is for user-level information and can be nullptr. |
host_nb | the number of hosts implied in the parallel task. |
host_list | an array of host_nb msg_host_t. |
flops_amount | an array of host_nb doubles. flops_amount[i] is the total number of operations that have to be performed on host_list[i]. |
bytes_amount | an array of host_nb* host_nb doubles. |
data | a pointer to any data may want to attach to the new object. It is for user-level information and can be nullptr. It can be retrieved with the function MSG_task_get_data. |
void* MSG_task_get_data | ( | msg_task_t | task | ) |
Return the user data of a msg_task_t.
This function checks whether task is a valid pointer and return the user data associated to task if possible.
void MSG_task_set_data | ( | msg_task_t | task, |
void * | data | ||
) |
Sets the user data of a msg_task_t.
This function allows to associate a new pointer to the user data associated of task.
void MSG_task_set_copy_callback | ( | void(*)(msg_task_t task, msg_process_t sender, msg_process_t receiver) | callback | ) |
Sets a function to be called when a task has just been copied.
callback | a callback function |
msg_process_t MSG_task_get_sender | ( | msg_task_t | task | ) |
Return the sender of a msg_task_t.
This functions returns the msg_process_t which sent this task
msg_host_t MSG_task_get_source | ( | msg_task_t | task | ) |
Return the source of a msg_task_t.
This functions returns the msg_host_t from which this task was sent
const char* MSG_task_get_name | ( | msg_task_t | task | ) |
Return the name of a msg_task_t.
This functions returns the name of a msg_task_t as specified on creation
void MSG_task_set_name | ( | msg_task_t | task, |
const char * | name | ||
) |
Sets the name of a msg_task_t.
This functions allows to associate a name to a task
msg_error_t MSG_task_destroy | ( | msg_task_t | task | ) |
Destroy a msg_task_t.
Destructor for msg_task_t. Note that you should free user data, if any, before calling this function.
Only the process that owns the task can destroy it. The owner changes after a successful send. If a task is successfully sent, the receiver becomes the owner and is supposed to destroy it. The sender should not use it anymore. If the task failed to be sent, the sender remains the owner of the task.
double MSG_task_get_remaining_work_ratio | ( | msg_task_t | task | ) |
Returns a value in ]0,1[ that represent the task remaining work to do: starts at 1 and goes to 0.
Returns 0 if not started or finished.
It works for either parallel or sequential tasks. TODO: Improve this function by returning 1 if the task has not started
double MSG_task_get_flops_amount | ( | msg_task_t | task | ) |
Returns the amount of flops that remain to be computed.
The returned value is initially the cost that you defined for the task, then it decreases until it reaches 0
It works for sequential tasks, but the remaining amount of work is not a scalar value for parallel tasks. So you will get an exception if you call this function on parallel tasks. Just don't do it.
void MSG_task_set_flops_amount | ( | msg_task_t | task, |
double | flops_amount | ||
) |
set the computation amount needed to process a task msg_task_t.
void MSG_task_set_bytes_amount | ( | msg_task_t | task, |
double | data_size | ||
) |
set the amount data attached with a task msg_task_t.
double MSG_task_get_remaining_communication | ( | msg_task_t | task | ) |
Returns the total amount received by a task msg_task_t.
If the communication does not exist it will return 0. So, if the communication has FINISHED or FAILED it returns zero.
double MSG_task_get_bytes_amount | ( | msg_task_t | task | ) |
Returns the size of the data attached to a task msg_task_t.
void MSG_task_set_priority | ( | msg_task_t | task, |
double | priority | ||
) |
Changes the priority of a computation task.
This priority doesn't affect the transfer rate. A priority of 2 will make a task receive two times more cpu power than the other ones.
void MSG_task_set_bound | ( | msg_task_t | task, |
double | bound | ||
) |
Changes the maximum CPU utilization of a computation task.
Unit is flops/s.
For VMs, there is a pitfall. Please see MSG_vm_set_bound().