1 /* Copyright (c) 2004-2018. The SimGrid Team. All rights reserved. */
3 /* This program is free software; you can redistribute it and/or modify it
4 * under the terms of the license (GNU LGPL) which comes with this package. */
6 #include "msg_private.hpp"
7 #include "src/simix/smx_private.hpp"
10 /** @addtogroup m_task_management
12 * Since most scheduling algorithms rely on a concept of task that can be either <em>computed</em> locally or
13 * <em>transferred</em> on another processor, it seems to be the right level of abstraction for our purposes.
14 * A <em>task</em> may then be defined by a <em>computing amount</em>, a <em>message size</em> and
15 * some <em>private data</em>.
18 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(msg_task, msg, "Logging specific to MSG (task)");
20 void s_simdata_task_t::reportMultipleUse() const
22 if (msg_global->debug_multiple_use){
23 XBT_ERROR("This task is already used in there:");
25 XBT_ERROR("<missing backtrace>");
26 XBT_ERROR("And you try to reuse it from here:");
27 xbt_backtrace_display_current();
29 xbt_die("This task is still being used somewhere else. You cannot send it now. Go fix your code!"
30 "(use --cfg=msg/debug-multiple-use:on to get the backtrace of the other process)");
34 /********************************* Task **************************************/
35 /** \ingroup m_task_management
36 * \brief Creates a new #msg_task_t.
38 * A constructor for #msg_task_t taking four arguments and returning the corresponding object.
39 * \param name a name for the object. It is for user-level information and can be nullptr.
40 * \param flop_amount a value of the processing amount (in flop) needed to process this new task.
41 * If 0, then it cannot be executed with MSG_task_execute(). This value has to be >=0.
42 * \param message_size a value of the amount of data (in bytes) needed to transfer this new task. If 0, then it cannot
43 * be transfered with MSG_task_send() and MSG_task_recv(). This value has to be >=0.
44 * \param data a pointer to any data may want to attach to the new object. It is for user-level information and can
45 * be nullptr. It can be retrieved with the function \ref MSG_task_get_data.
47 * \return The new corresponding object.
49 msg_task_t MSG_task_create(const char *name, double flop_amount, double message_size, void *data)
51 msg_task_t task = new s_msg_task_t;
52 simdata_task_t simdata = new s_simdata_task_t();
53 task->simdata = simdata;
56 task->name = xbt_strdup(name);
60 simdata->bytes_amount = message_size;
61 simdata->flops_amount = flop_amount;
63 TRACE_msg_task_create(task);
68 /** \ingroup m_task_management
69 * \brief Creates a new #msg_task_t (a parallel one....).
71 * A constructor for #msg_task_t taking six arguments and returning the corresponding object.
72 * \param name a name for the object. It is for user-level information and can be nullptr.
73 * \param host_nb the number of hosts implied in the parallel task.
74 * \param host_list an array of \p host_nb msg_host_t.
75 * \param flops_amount an array of \p host_nb doubles.
76 * flops_amount[i] is the total number of operations that have to be performed on host_list[i].
77 * \param bytes_amount an array of \p host_nb* \p host_nb doubles.
78 * \param data a pointer to any data may want to attach to the new object.
79 * It is for user-level information and can be nullptr.
80 * It can be retrieved with the function \ref MSG_task_get_data.
82 * \return The new corresponding object.
84 msg_task_t MSG_parallel_task_create(const char *name, int host_nb, const msg_host_t * host_list,
85 double *flops_amount, double *bytes_amount, void *data)
87 // Task's flops amount is set to an arbitrary value > 0.0 to be able to distinguish, in
88 // MSG_task_get_remaining_work_ratio(), a finished task and a task that has not started yet.
89 msg_task_t task = MSG_task_create(name, 1.0, 0, data);
90 simdata_task_t simdata = task->simdata;
92 /* Simulator Data specific to parallel tasks */
93 simdata->host_nb = host_nb;
94 simdata->host_list = new sg_host_t[host_nb];
95 std::copy_n(host_list, host_nb, simdata->host_list);
96 if (flops_amount != nullptr) {
97 simdata->flops_parallel_amount = new double[host_nb];
98 std::copy_n(flops_amount, host_nb, simdata->flops_parallel_amount);
100 if (bytes_amount != nullptr) {
101 simdata->bytes_parallel_amount = new double[host_nb * host_nb];
102 std::copy_n(bytes_amount, host_nb * host_nb, simdata->bytes_parallel_amount);
108 /** \ingroup m_task_management
109 * \brief Return the user data of a #msg_task_t.
111 * This function checks whether \a task is a valid pointer and return the user data associated to \a task if possible.
113 void *MSG_task_get_data(msg_task_t task)
118 /** \ingroup m_task_management
119 * \brief Sets the user data of a #msg_task_t.
121 * This function allows to associate a new pointer to the user data associated of \a task.
123 void MSG_task_set_data(msg_task_t task, void *data)
128 /** \ingroup m_task_management
129 * \brief Sets a function to be called when a task has just been copied.
130 * \param callback a callback function
132 void MSG_task_set_copy_callback(void (*callback) (msg_task_t task, msg_process_t sender, msg_process_t receiver)) {
134 msg_global->task_copy_callback = callback;
137 SIMIX_comm_set_copy_data_callback(MSG_comm_copy_data_from_SIMIX);
139 SIMIX_comm_set_copy_data_callback(SIMIX_comm_copy_pointer_callback);
143 /** \ingroup m_task_management
144 * \brief Return the sender of a #msg_task_t.
146 * This functions returns the #msg_process_t which sent this task
148 msg_process_t MSG_task_get_sender(msg_task_t task)
150 return task->simdata->sender;
153 /** \ingroup m_task_management
154 * \brief Return the source of a #msg_task_t.
156 * This functions returns the #msg_host_t from which this task was sent
158 msg_host_t MSG_task_get_source(msg_task_t task)
160 return task->simdata->source;
163 /** \ingroup m_task_management
164 * \brief Return the name of a #msg_task_t.
166 * This functions returns the name of a #msg_task_t as specified on creation
168 const char *MSG_task_get_name(msg_task_t task)
173 /** \ingroup m_task_management
174 * \brief Sets the name of a #msg_task_t.
176 * This functions allows to associate a name to a task
178 void MSG_task_set_name(msg_task_t task, const char *name)
180 task->name = xbt_strdup(name);
183 /** \ingroup m_task_management
184 * \brief Destroy a #msg_task_t.
186 * Destructor for #msg_task_t. Note that you should free user data, if any, \b before calling this function.
188 * Only the process that owns the task can destroy it.
189 * The owner changes after a successful send.
190 * If a task is successfully sent, the receiver becomes the owner and is supposed to destroy it. The sender should not
192 * If the task failed to be sent, the sender remains the owner of the task.
194 msg_error_t MSG_task_destroy(msg_task_t task)
196 if (task->simdata->isused) {
197 /* the task is being sent or executed: cancel it first */
198 MSG_task_cancel(task);
200 TRACE_msg_task_destroy(task);
202 xbt_free(task->name);
204 /* free main structures */
205 delete task->simdata;
211 /** \ingroup m_task_usage
212 * \brief Cancel a #msg_task_t.
213 * \param task the task to cancel. If it was executed or transfered, it stops the process that were working on it.
215 msg_error_t MSG_task_cancel(msg_task_t task)
217 xbt_assert((task != nullptr), "Cannot cancel a nullptr task");
219 simdata_task_t simdata = task->simdata;
220 if (simdata->compute) {
221 simcall_execution_cancel(simdata->compute);
222 } else if (simdata->comm) {
223 simcall_comm_cancel(simdata->comm);
225 simdata->setNotUsed();
229 /** \ingroup m_task_management
230 * \brief Returns a value in ]0,1[ that represent the task remaining work
231 * to do: starts at 1 and goes to 0. Returns 0 if not started or finished.
233 * It works for either parallel or sequential tasks.
235 double MSG_task_get_remaining_work_ratio(msg_task_t task) {
237 xbt_assert((task != nullptr), "Cannot get information from a nullptr task");
238 if (task->simdata->compute) {
240 return task->simdata->compute->remainingRatio();
242 // Task not started (flops_amount is > 0.0) or finished (flops_amount is set to 0.0)
243 return task->simdata->flops_amount > 0.0 ? 1.0 : 0.0;
247 /** \ingroup m_task_management
248 * \brief Returns the amount of flops that remain to be computed
250 * The returned value is initially the cost that you defined for the task, then it decreases until it reaches 0
252 * It works for sequential tasks, but the remaining amount of work is not a scalar value for parallel tasks.
253 * So you will get an exception if you call this function on parallel tasks. Just don't do it.
255 double MSG_task_get_flops_amount(msg_task_t task) {
256 if (task->simdata->compute != nullptr) {
257 return task->simdata->compute->remains();
259 // Not started or already done.
260 // - Before starting, flops_amount is initially the task cost
261 // - After execution, flops_amount is set to 0 (until someone uses MSG_task_set_flops_amount, if any)
262 return task->simdata->flops_amount;
266 /** \ingroup m_task_management
267 * \brief set the computation amount needed to process a task #msg_task_t.
269 * \warning If the computation is ongoing (already started and not finished),
270 * it is not modified by this call. Moreover, after its completion, the ongoing execution with set the flops_amount to
271 * zero, overriding any value set during the execution.
273 void MSG_task_set_flops_amount(msg_task_t task, double flops_amount)
275 task->simdata->flops_amount = flops_amount;
278 /** \ingroup m_task_management
279 * \brief set the amount data attached with a task #msg_task_t.
281 * \warning If the transfer is ongoing (already started and not finished), it is not modified by this call.
283 void MSG_task_set_bytes_amount(msg_task_t task, double data_size)
285 task->simdata->bytes_amount = data_size;
288 /** \ingroup m_task_management
289 * \brief Returns the total amount received by a task #msg_task_t.
290 * If the communication does not exist it will return 0.
291 * So, if the communication has FINISHED or FAILED it returns zero.
293 double MSG_task_get_remaining_communication(msg_task_t task)
295 XBT_DEBUG("calling simcall_communication_get_remains(%p)", task->simdata->comm.get());
296 return task->simdata->comm->remains();
299 /** \ingroup m_task_management
300 * \brief Returns the size of the data attached to a task #msg_task_t.
302 double MSG_task_get_bytes_amount(msg_task_t task)
304 xbt_assert((task != nullptr) && (task->simdata != nullptr), "Invalid parameter");
305 return task->simdata->bytes_amount;
308 /** \ingroup m_task_management
309 * \brief Changes the priority of a computation task. This priority doesn't affect the transfer rate. A priority of 2
310 * will make a task receive two times more cpu power than the other ones.
312 void MSG_task_set_priority(msg_task_t task, double priority)
314 task->simdata->priority = 1 / priority;
315 if (task->simdata->compute)
316 simcall_execution_set_priority(task->simdata->compute, task->simdata->priority);
319 /** \ingroup m_task_management
320 * \brief Changes the maximum CPU utilization of a computation task.
323 * For VMs, there is a pitfall. Please see MSG_vm_set_bound().
325 void MSG_task_set_bound(msg_task_t task, double bound)
327 if (bound < 1e-12) /* close enough to 0 without any floating precision surprise */
328 XBT_INFO("bound == 0 means no capping (i.e., unlimited).");
330 task->simdata->bound = bound;
331 if (task->simdata->compute)
332 simcall_execution_set_bound(task->simdata->compute, task->simdata->bound);