src/simdag/sd_task.c

   1 /* Copyright (c) 2006, 2007, 2008, 2009, 2010, 2011. The SimGrid Team.
   2  * All rights reserved.                                                     */
   3
   4 /* This program is free software; you can redistribute it and/or modify it
   5  * under the terms of the license (GNU LGPL) which comes with this package. */
   6
   7 #include "private.h"
   8 #include "simdag/simdag.h"
   9 #include "xbt/sysdep.h"
  10 #include "xbt/dynar.h"
  11 #include "instr/instr_private.h"
  12
  13 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(sd_task, sd,
  14                                 "Logging specific to SimDag (task)");
  15
  16 static void __SD_task_remove_dependencies(SD_task_t task);
  17 static void __SD_task_destroy_scheduling_data(SD_task_t task);
  18
  19 void* SD_task_new_f(void)
  20 {
  21   SD_task_t task = xbt_new0(s_SD_task_t, 1);
  22   task->tasks_before = xbt_dynar_new(sizeof(SD_dependency_t), NULL);
  23   task->tasks_after = xbt_dynar_new(sizeof(SD_dependency_t), NULL);
  24
  25   return task;
  26 }
  27
  28 void SD_task_recycle_f(void *t)
  29 {
  30   SD_task_t task = (SD_task_t) t;
  31
  32   /* Reset the content */
  33   task->kind = SD_TASK_NOT_TYPED;
  34   task->state_hookup.prev = NULL;
  35   task->state_hookup.next = NULL;
  36   task->state_set = sd_global->not_scheduled_task_set;
  37   xbt_swag_insert(task, task->state_set);
  38   task->state = SD_NOT_SCHEDULED;
  39   task->return_hookup.prev = NULL;
  40   task->return_hookup.next = NULL;
  41
  42   task->marked = 0;
  43
  44   task->start_time = -1.0;
  45   task->finish_time = -1.0;
  46   task->surf_action = NULL;
  47   task->watch_points = 0;
  48
  49   /* dependencies */
  50   xbt_dynar_reset(task->tasks_before);
  51   xbt_dynar_reset(task->tasks_after);
  52   task->unsatisfied_dependencies = 0;
  53   task->is_not_ready = 0;
  54
  55   /* scheduling parameters */
  56   task->workstation_nb = 0;
  57   task->workstation_list = NULL;
  58   task->computation_amount = NULL;
  59   task->communication_amount = NULL;
  60   task->rate = -1;
  61 }
  62
  63 void SD_task_free_f(void *t)
  64 {
  65   SD_task_t task = (SD_task_t)t;
  66
  67   xbt_dynar_free(&task->tasks_before);
  68   xbt_dynar_free(&task->tasks_after);
  69   xbt_free(task);
  70 }
  71
  72 /**
  73  * \brief Creates a new task.
  74  *
  75  * \param name the name of the task (can be \c NULL)
  76  * \param data the user data you want to associate with the task (can be \c NULL)
  77  * \param amount amount of the task
  78  * \return the new task
  79  * \see SD_task_destroy()
  80  */
  81 SD_task_t SD_task_create(const char *name, void *data, double amount)
  82 {
  83   SD_task_t task = xbt_mallocator_get(sd_global->task_mallocator);
  84
  85   /* general information */
  86   task->data = data;            /* user data */
  87   task->name = xbt_strdup(name);
  88   task->amount = amount;
  89   task->remains = amount;
  90
  91   sd_global->task_number++;
  92
  93 #ifdef HAVE_TRACING
  94   task->category = NULL;
  95 #endif
  96
  97   return task;
  98 }
  99
 100 static XBT_INLINE SD_task_t SD_task_create_sized(const char *name,
 101                                                  void *data, double amount,
 102                                                  int ws_count)
 103 {
 104   SD_task_t task = SD_task_create(name, data, amount);
 105   task->communication_amount = xbt_new0(double, ws_count * ws_count);
 106   task->computation_amount = xbt_new0(double, ws_count);
 107   task->workstation_nb = ws_count;
 108   task->workstation_list = xbt_new0(SD_workstation_t, ws_count);
 109   return task;
 110 }
 111
 112 /** @brief create a end-to-end communication task that can then be auto-scheduled
 113  *
 114  * Auto-scheduling mean that the task can be used with SD_task_schedulev(). This
 115  * allows to specify the task costs at creation, and decouple them from the
 116  * scheduling process where you just specify which resource should deliver the
 117  * mandatory power.
 118  *
 119  * A end-to-end communication must be scheduled on 2 hosts, and the amount
 120  * specified at creation is sent from hosts[0] to hosts[1].
 121  */
 122 SD_task_t SD_task_create_comm_e2e(const char *name, void *data,
 123                                   double amount)
 124 {
 125   SD_task_t res = SD_task_create_sized(name, data, amount, 2);
 126   res->communication_amount[2] = amount;
 127   res->kind = SD_TASK_COMM_E2E;
 128   return res;
 129 }
 130
 131 /** @brief create a sequential computation task that can then be auto-scheduled
 132  *
 133  * Auto-scheduling mean that the task can be used with SD_task_schedulev(). This
 134  * allows to specify the task costs at creation, and decouple them from the
 135  * scheduling process where you just specify which resource should deliver the
 136  * mandatory power.
 137  *
 138  * A sequential computation must be scheduled on 1 host, and the amount
 139  * specified at creation to be run on hosts[0].
 140  *
 141  * \param name the name of the task (can be \c NULL)
 142  * \param data the user data you want to associate with the task (can be \c NULL)
 143  * \param amount amount of compute work to be done by the task
 144  * \return the new SD_TASK_COMP_SEQ typed task
 145  */
 146 SD_task_t SD_task_create_comp_seq(const char *name, void *data,
 147                                   double amount)
 148 {
 149   SD_task_t res = SD_task_create_sized(name, data, amount, 1);
 150   res->computation_amount[0] = amount;
 151   res->kind = SD_TASK_COMP_SEQ;
 152   return res;
 153 }
 154
 155 /** @brief create a parallel computation task that can then be auto-scheduled
 156  *
 157  * Auto-scheduling mean that the task can be used with SD_task_schedulev(). This
 158  * allows to specify the task costs at creation, and decouple them from the
 159  * scheduling process where you just specify which resource should deliver the
 160  * mandatory power.
 161  *
 162  * A parallel computation can be scheduled on any number of host.
 163  * The underlying speedup model is Amdahl's law.
 164  * To be auto-scheduled, \see SD_task_distribute_comp_amdhal has to be called
 165  * first.
 166  * \param name the name of the task (can be \c NULL)
 167  * \param data the user data you want to associate with the task (can be \c NULL)
 168  * \param amount amount of compute work to be done by the task
 169  * \param purely serial fraction of the work to be done (in [0.;1.[)
 170  * \return the new task
 171  */
 172 SD_task_t SD_task_create_comp_par_amdahl(const char *name, void *data,
 173                                   double amount, double alpha)
 174 {
 175   xbt_assert(alpha < 1. && alpha >= 0.,
 176               "Invalid parameter: alpha must be in [0.;1.[");
 177
 178   SD_task_t res = SD_task_create(name, data, amount);
 179   res->alpha = alpha;
 180   res->kind = SD_TASK_COMP_PAR_AMDAHL;
 181   return res;
 182 }
 183
 184
 185 /**
 186  * \brief Destroys a task.
 187  *
 188  * The user data (if any) should have been destroyed first.
 189  *
 190  * \param task the task you want to destroy
 191  * \see SD_task_create()
 192  */
 193 void SD_task_destroy(SD_task_t task)
 194 {
 195   XBT_DEBUG("Destroying task %s...", SD_task_get_name(task));
 196
 197   __SD_task_remove_dependencies(task);
 198   /* if the task was scheduled or runnable we have to free the scheduling parameters */
 199   if (__SD_task_is_scheduled_or_runnable(task))
 200     __SD_task_destroy_scheduling_data(task);
 201   if (task->state_set != NULL) /* would be null if just created */
 202     xbt_swag_remove(task, task->state_set);
 203
 204   xbt_swag_remove(task, sd_global->return_set);
 205
 206   xbt_free(task->name);
 207
 208   if (task->surf_action != NULL)
 209     surf_workstation_model->action_unref(task->surf_action);
 210
 211   xbt_free(task->workstation_list);
 212   xbt_free(task->communication_amount);
 213   xbt_free(task->computation_amount);
 214
 215   xbt_mallocator_release(sd_global->task_mallocator,task);
 216   sd_global->task_number--;
 217
 218 #ifdef HAVE_TRACING
 219   if (task->category) xbt_free(task->category);
 220 #endif
 221
 222   XBT_DEBUG("Task destroyed.");
 223 }
 224
 225 /**
 226  * \brief Returns the user data of a task
 227  *
 228  * \param task a task
 229  * \return the user data associated with this task (can be \c NULL)
 230  * \see SD_task_set_data()
 231  */
 232 void *SD_task_get_data(SD_task_t task)
 233 {
 234   return task->data;
 235 }
 236
 237 /**
 238  * \brief Sets the user data of a task
 239  *
 240  * The new data can be \c NULL. The old data should have been freed first
 241  * if it was not \c NULL.
 242  *
 243  * \param task a task
 244  * \param data the new data you want to associate with this task
 245  * \see SD_task_get_data()
 246  */
 247 void SD_task_set_data(SD_task_t task, void *data)
 248 {
 249   task->data = data;
 250 }
 251
 252 /**
 253  * \brief Returns the state of a task
 254  *
 255  * \param task a task
 256  * \return the current \ref e_SD_task_state_t "state" of this task:
 257  * #SD_NOT_SCHEDULED, #SD_SCHEDULED, #SD_RUNNABLE, #SD_RUNNING, #SD_DONE or #SD_FAILED
 258  * \see e_SD_task_state_t
 259  */
 260 e_SD_task_state_t SD_task_get_state(SD_task_t task)
 261 {
 262   return task->state;
 263 }
 264
 265 /* Changes the state of a task. Updates the swags and the flag sd_global->watch_point_reached.
 266  */
 267 void __SD_task_set_state(SD_task_t task, e_SD_task_state_t new_state)
 268 {
 269   xbt_swag_remove(task, task->state_set);
 270   switch (new_state) {
 271   case SD_NOT_SCHEDULED:
 272     task->state_set = sd_global->not_scheduled_task_set;
 273     break;
 274   case SD_SCHEDULABLE:
 275     task->state_set = sd_global->schedulable_task_set;
 276     break;
 277   case SD_SCHEDULED:
 278     task->state_set = sd_global->scheduled_task_set;
 279     break;
 280   case SD_RUNNABLE:
 281     task->state_set = sd_global->runnable_task_set;
 282     break;
 283   case SD_IN_FIFO:
 284     task->state_set = sd_global->in_fifo_task_set;
 285     break;
 286   case SD_RUNNING:
 287     task->state_set = sd_global->running_task_set;
 288     task->start_time =
 289         surf_workstation_model->action_get_start_time(task->surf_action);
 290     break;
 291   case SD_DONE:
 292     task->state_set = sd_global->done_task_set;
 293     task->finish_time =
 294         surf_workstation_model->action_get_finish_time(task->surf_action);
 295     task->remains = 0;
 296 #ifdef HAVE_JEDULE
 297     jedule_log_sd_event(task);
 298 #endif
 299     break;
 300   case SD_FAILED:
 301     task->state_set = sd_global->failed_task_set;
 302     break;
 303   default:
 304     xbt_die( "Invalid state");
 305   }
 306   xbt_swag_insert(task, task->state_set);
 307   task->state = new_state;
 308
 309   if (task->watch_points & new_state) {
 310     XBT_VERB("Watch point reached with task '%s'!", SD_task_get_name(task));
 311     sd_global->watch_point_reached = 1;
 312     SD_task_unwatch(task, new_state);   /* remove the watch point */
 313   }
 314 }
 315
 316 /**
 317  * \brief Returns the name of a task
 318  *
 319  * \param task a task
 320  * \return the name of this task (can be \c NULL)
 321  */
 322 const char *SD_task_get_name(SD_task_t task)
 323 {
 324   return task->name;
 325 }
 326
 327 /** @brief Allows to change the name of a task */
 328 void SD_task_set_name(SD_task_t task, const char *name)
 329 {
 330   xbt_free(task->name);
 331   task->name = xbt_strdup(name);
 332 }
 333
 334 /** @brief Returns the dynar of the parents of a task
 335  *
 336  * \param task a task
 337  * \return a newly allocated dynar comprising the parents of this task
 338  */
 339
 340 xbt_dynar_t SD_task_get_parents(SD_task_t task)
 341 {
 342   unsigned int i;
 343   xbt_dynar_t parents;
 344   SD_dependency_t dep;
 345
 346   parents = xbt_dynar_new(sizeof(SD_task_t), NULL);
 347   xbt_dynar_foreach(task->tasks_before, i, dep) {
 348     xbt_dynar_push(parents, &(dep->src));
 349   }
 350   return parents;
 351 }
 352
 353 /** @brief Returns the dynar of the parents of a task
 354  *
 355  * \param task a task
 356  * \return a newly allocated dynar comprising the parents of this task
 357  */
 358 xbt_dynar_t SD_task_get_children(SD_task_t task)
 359 {
 360   unsigned int i;
 361   xbt_dynar_t children;
 362   SD_dependency_t dep;
 363
 364   children = xbt_dynar_new(sizeof(SD_task_t), NULL);
 365   xbt_dynar_foreach(task->tasks_after, i, dep) {
 366     xbt_dynar_push(children, &(dep->dst));
 367   }
 368   return children;
 369 }
 370
 371 /**
 372  * \brief Returns the amount of workstations involved in a task
 373  *
 374  * Only call this on already scheduled tasks!
 375  * \param task a task
 376  */
 377 int SD_task_get_workstation_count(SD_task_t task)
 378 {
 379   return task->workstation_nb;
 380 }
 381
 382 /**
 383  * \brief Returns the list of workstations involved in a task
 384  *
 385  * Only call this on already scheduled tasks!
 386  * \param task a task
 387  */
 388 SD_workstation_t *SD_task_get_workstation_list(SD_task_t task)
 389 {
 390   return task->workstation_list;
 391 }
 392
 393 /**
 394  * \brief Returns the total amount of work contained in a task
 395  *
 396  * \param task a task
 397  * \return the total amount of work (computation or data transfer) for this task
 398  * \see SD_task_get_remaining_amount()
 399  */
 400 double SD_task_get_amount(SD_task_t task)
 401 {
 402   return task->amount;
 403 }
 404
 405 /**
 406  * \brief Returns the remaining amount work to do till the completion of a task
 407  *
 408  * \param task a task
 409  * \return the remaining amount of work (computation or data transfer) of this task
 410  * \see SD_task_get_amount()
 411  */
 412 double SD_task_get_remaining_amount(SD_task_t task)
 413 {
 414   if (task->surf_action)
 415     return surf_workstation_model->get_remains(task->surf_action);
 416   else
 417     return task->remains;
 418 }
 419
 420 int SD_task_get_kind(SD_task_t task)
 421 {
 422   return task->kind;
 423 }
 424
 425 /** @brief Displays debugging informations about a task */
 426 void SD_task_dump(SD_task_t task)
 427 {
 428   unsigned int counter;
 429   SD_dependency_t dependency;
 430   char *statename;
 431
 432   XBT_INFO("Displaying task %s", SD_task_get_name(task));
 433   statename = bprintf("%s %s %s %s %s %s %s %s",
 434                       (task->state & SD_NOT_SCHEDULED ? "not scheduled" :
 435                        ""),
 436                       (task->state & SD_SCHEDULABLE ? "schedulable" : ""),
 437                       (task->state & SD_SCHEDULED ? "scheduled" : ""),
 438                       (task->state & SD_RUNNABLE ? "runnable" :
 439                        "not runnable"),
 440                       (task->state & SD_IN_FIFO ? "in fifo" : ""),
 441                       (task->state & SD_RUNNING ? "running" : ""),
 442                       (task->state & SD_DONE ? "done" : ""),
 443                       (task->state & SD_FAILED ? "failed" : ""));
 444   XBT_INFO("  - state: %s", statename);
 445   free(statename);
 446
 447   if (task->kind != 0) {
 448     switch (task->kind) {
 449     case SD_TASK_COMM_E2E:
 450       XBT_INFO("  - kind: end-to-end communication");
 451       break;
 452     case SD_TASK_COMP_SEQ:
 453       XBT_INFO("  - kind: sequential computation");
 454       break;
 455     case SD_TASK_COMP_PAR_AMDAHL:
 456       XBT_INFO("  - kind: parallel computation following Amdahl's law");
 457       break;
 458     default:
 459       XBT_INFO("  - (unknown kind %d)", task->kind);
 460     }
 461   }
 462   XBT_INFO("  - amount: %.0f", SD_task_get_amount(task));
 463   XBT_INFO("  - Dependencies to satisfy: %u", task->unsatisfied_dependencies);
 464   if (!xbt_dynar_is_empty(task->tasks_before)) {
 465     XBT_INFO("  - pre-dependencies:");
 466     xbt_dynar_foreach(task->tasks_before, counter, dependency) {
 467       XBT_INFO("    %s", SD_task_get_name(dependency->src));
 468     }
 469   }
 470   if (!xbt_dynar_is_empty(task->tasks_after)) {
 471     XBT_INFO("  - post-dependencies:");
 472     xbt_dynar_foreach(task->tasks_after, counter, dependency) {
 473       XBT_INFO("    %s", SD_task_get_name(dependency->dst));
 474     }
 475   }
 476 }
 477
 478 /** @brief Dumps the task in dotty formalism into the FILE* passed as second argument */
 479 void SD_task_dotty(SD_task_t task, void *out)
 480 {
 481   unsigned int counter;
 482   SD_dependency_t dependency;
 483   fprintf(out, "  T%p [label=\"%.20s\"", task, task->name);
 484   switch (task->kind) {
 485   case SD_TASK_COMM_E2E:
 486     fprintf(out, ", shape=box");
 487     break;
 488   case SD_TASK_COMP_SEQ:
 489     fprintf(out, ", shape=circle");
 490     break;
 491   default:
 492     xbt_die("Unknown task type!");
 493   }
 494   fprintf(out, "];\n");
 495   xbt_dynar_foreach(task->tasks_before, counter, dependency) {
 496     fprintf(out, " T%p -> T%p;\n", dependency->src, dependency->dst);
 497   }
 498 }
 499
 500 /* Destroys a dependency between two tasks.
 501  */
 502 static void __SD_task_dependency_destroy(void *dependency)
 503 {
 504   xbt_free(((SD_dependency_t)dependency)->name);
 505   xbt_free(dependency);
 506 }
 507
 508 /**
 509  * \brief Adds a dependency between two tasks
 510  *
 511  * \a dst will depend on \a src, ie \a dst will not start before \a src is finished.
 512  * Their \ref e_SD_task_state_t "state" must be #SD_NOT_SCHEDULED, #SD_SCHEDULED or #SD_RUNNABLE.
 513  *
 514  * \param name the name of the new dependency (can be \c NULL)
 515  * \param data the user data you want to associate with this dependency (can be \c NULL)
 516  * \param src the task which must be executed first
 517  * \param dst the task you want to make depend on \a src
 518  * \see SD_task_dependency_remove()
 519  */
 520 void SD_task_dependency_add(const char *name, void *data, SD_task_t src,
 521                             SD_task_t dst)
 522 {
 523   xbt_dynar_t dynar;
 524   int length;
 525   int found = 0;
 526   int i;
 527   SD_dependency_t dependency;
 528
 529   dynar = src->tasks_after;
 530   length = xbt_dynar_length(dynar);
 531
 532   if (src == dst)
 533     THROWF(arg_error, 0,
 534            "Cannot add a dependency between task '%s' and itself",
 535            SD_task_get_name(src));
 536
 537   if (!__SD_task_is_not_scheduled(src) && !__SD_task_is_schedulable(src)
 538       && !__SD_task_is_scheduled_or_runnable(src) && !__SD_task_is_running(src))
 539     THROWF(arg_error, 0,
 540            "Task '%s' must be SD_NOT_SCHEDULED, SD_SCHEDULABLE, SD_SCHEDULED or SD_RUNNABLE"
 541            " or SD_RUNNING",
 542            SD_task_get_name(src));
 543
 544   if (!__SD_task_is_not_scheduled(dst) && !__SD_task_is_schedulable(dst)
 545       && !__SD_task_is_scheduled_or_runnable(dst))
 546     THROWF(arg_error, 0,
 547            "Task '%s' must be SD_NOT_SCHEDULED, SD_SCHEDULABLE, SD_SCHEDULED or SD_RUNNABLE",
 548            SD_task_get_name(dst));
 549
 550   XBT_DEBUG("SD_task_dependency_add: src = %s, dst = %s",
 551          SD_task_get_name(src), SD_task_get_name(dst));
 552   for (i = 0; i < length && !found; i++) {
 553     xbt_dynar_get_cpy(dynar, i, &dependency);
 554     found = (dependency->dst == dst);
 555     XBT_DEBUG("Dependency %d: dependency->dst = %s", i,
 556            SD_task_get_name(dependency->dst));
 557   }
 558
 559   if (found)
 560     THROWF(arg_error, 0,
 561            "A dependency already exists between task '%s' and task '%s'",
 562            SD_task_get_name(src), SD_task_get_name(dst));
 563
 564   dependency = xbt_new(s_SD_dependency_t, 1);
 565
 566   dependency->name = xbt_strdup(name);  /* xbt_strdup is cleaver enough to deal with NULL args itself */
 567   dependency->data = data;
 568   dependency->src = src;
 569   dependency->dst = dst;
 570
 571   /* src must be executed before dst */
 572   xbt_dynar_push(src->tasks_after, &dependency);
 573   xbt_dynar_push(dst->tasks_before, &dependency);
 574
 575   dst->unsatisfied_dependencies++;
 576   dst->is_not_ready++;
 577
 578   /* if the task was runnable, then dst->tasks_before is not empty anymore,
 579      so we must go back to state SD_SCHEDULED */
 580   if (__SD_task_is_runnable(dst)) {
 581     XBT_DEBUG
 582         ("SD_task_dependency_add: %s was runnable and becomes scheduled!",
 583          SD_task_get_name(dst));
 584     __SD_task_set_state(dst, SD_SCHEDULED);
 585   }
 586
 587   /*  __SD_print_dependencies(src);
 588      __SD_print_dependencies(dst); */
 589 }
 590
 591 /**
 592  * \brief Indicates whether there is a dependency between two tasks.
 593  *
 594  * \param src a task
 595  * \param dst a task depending on \a src
 596  *
 597  * If src is NULL, checks whether dst has any pre-dependency.
 598  * If dst is NULL, checks whether src has any post-dependency.
 599  */
 600 int SD_task_dependency_exists(SD_task_t src, SD_task_t dst)
 601 {
 602   unsigned int counter;
 603   SD_dependency_t dependency;
 604
 605   xbt_assert(src != NULL
 606               || dst != NULL,
 607               "Invalid parameter: both src and dst are NULL");
 608
 609   if (src) {
 610     if (dst) {
 611       xbt_dynar_foreach(src->tasks_after, counter, dependency) {
 612         if (dependency->dst == dst)
 613           return 1;
 614       }
 615     } else {
 616       return xbt_dynar_length(src->tasks_after);
 617     }
 618   } else {
 619     return xbt_dynar_length(dst->tasks_before);
 620   }
 621   return 0;
 622 }
 623
 624 /**
 625  * \brief Remove a dependency between two tasks
 626  *
 627  * \param src a task
 628  * \param dst a task depending on \a src
 629  * \see SD_task_dependency_add()
 630  */
 631 void SD_task_dependency_remove(SD_task_t src, SD_task_t dst)
 632 {
 633
 634   xbt_dynar_t dynar;
 635   int length;
 636   int found = 0;
 637   int i;
 638   SD_dependency_t dependency;
 639
 640   /* remove the dependency from src->tasks_after */
 641   dynar = src->tasks_after;
 642   length = xbt_dynar_length(dynar);
 643
 644   for (i = 0; i < length && !found; i++) {
 645     xbt_dynar_get_cpy(dynar, i, &dependency);
 646     if (dependency->dst == dst) {
 647       xbt_dynar_remove_at(dynar, i, NULL);
 648       found = 1;
 649     }
 650   }
 651   if (!found)
 652     THROWF(arg_error, 0,
 653            "No dependency found between task '%s' and '%s': task '%s' is not a successor of task '%s'",
 654            SD_task_get_name(src), SD_task_get_name(dst),
 655            SD_task_get_name(dst), SD_task_get_name(src));
 656
 657   /* remove the dependency from dst->tasks_before */
 658   dynar = dst->tasks_before;
 659   length = xbt_dynar_length(dynar);
 660   found = 0;
 661
 662   for (i = 0; i < length && !found; i++) {
 663     xbt_dynar_get_cpy(dynar, i, &dependency);
 664     if (dependency->src == src) {
 665       xbt_dynar_remove_at(dynar, i, NULL);
 666       __SD_task_dependency_destroy(dependency);
 667       dst->unsatisfied_dependencies--;
 668       dst->is_not_ready--;
 669       found = 1;
 670     }
 671   }
 672   /* should never happen... */
 673   xbt_assert(found,
 674               "SimDag error: task '%s' is a successor of '%s' but task '%s' is not a predecessor of task '%s'",
 675               SD_task_get_name(dst), SD_task_get_name(src),
 676               SD_task_get_name(src), SD_task_get_name(dst));
 677
 678   /* if the task was scheduled and dst->tasks_before is empty now, we can make it runnable */
 679
 680   if (dst->unsatisfied_dependencies == 0) {
 681     if (__SD_task_is_scheduled(dst))
 682       __SD_task_set_state(dst, SD_RUNNABLE);
 683     else
 684       __SD_task_set_state(dst, SD_SCHEDULABLE);
 685   }
 686
 687   if (dst->is_not_ready == 0)
 688     __SD_task_set_state(dst, SD_SCHEDULABLE);
 689
 690   /*  __SD_print_dependencies(src);
 691      __SD_print_dependencies(dst); */
 692 }
 693
 694 /**
 695  * \brief Returns the user data associated with a dependency between two tasks
 696  *
 697  * \param src a task
 698  * \param dst a task depending on \a src
 699  * \return the user data associated with this dependency (can be \c NULL)
 700  * \see SD_task_dependency_add()
 701  */
 702 void *SD_task_dependency_get_data(SD_task_t src, SD_task_t dst)
 703 {
 704
 705   xbt_dynar_t dynar;
 706   int length;
 707   int found = 0;
 708   int i;
 709   SD_dependency_t dependency;
 710
 711   dynar = src->tasks_after;
 712   length = xbt_dynar_length(dynar);
 713
 714   for (i = 0; i < length && !found; i++) {
 715     xbt_dynar_get_cpy(dynar, i, &dependency);
 716     found = (dependency->dst == dst);
 717   }
 718   if (!found)
 719     THROWF(arg_error, 0, "No dependency found between task '%s' and '%s'",
 720            SD_task_get_name(src), SD_task_get_name(dst));
 721   return dependency->data;
 722 }
 723
 724 /* temporary function for debugging */
 725 static void __SD_print_watch_points(SD_task_t task)
 726 {
 727   static const int state_masks[] =
 728       { SD_SCHEDULABLE, SD_SCHEDULED, SD_RUNNING, SD_RUNNABLE, SD_DONE,
 729     SD_FAILED
 730   };
 731   static const char *state_names[] =
 732       { "schedulable", "scheduled", "running", "runnable", "done",
 733     "failed"
 734   };
 735   int i;
 736
 737   XBT_INFO("Task '%s' watch points (%x): ", SD_task_get_name(task),
 738         task->watch_points);
 739
 740
 741   for (i = 0; i < 5; i++) {
 742     if (task->watch_points & state_masks[i])
 743       XBT_INFO("%s ", state_names[i]);
 744   }
 745 }
 746
 747 /**
 748  * \brief Adds a watch point to a task
 749  *
 750  * SD_simulate() will stop as soon as the \ref e_SD_task_state_t "state" of this
 751  * task becomes the one given in argument. The
 752  * watch point is then automatically removed.
 753  *
 754  * \param task a task
 755  * \param state the \ref e_SD_task_state_t "state" you want to watch
 756  * (cannot be #SD_NOT_SCHEDULED)
 757  * \see SD_task_unwatch()
 758  */
 759 void SD_task_watch(SD_task_t task, e_SD_task_state_t state)
 760 {
 761   if (state & SD_NOT_SCHEDULED)
 762     THROWF(arg_error, 0,
 763            "Cannot add a watch point for state SD_NOT_SCHEDULED");
 764
 765   task->watch_points = task->watch_points | state;
 766   /*  __SD_print_watch_points(task); */
 767 }
 768
 769 /**
 770  * \brief Removes a watch point from a task
 771  *
 772  * \param task a task
 773  * \param state the \ref e_SD_task_state_t "state" you no longer want to watch
 774  * \see SD_task_watch()
 775  */
 776 void SD_task_unwatch(SD_task_t task, e_SD_task_state_t state)
 777 {
 778   xbt_assert(state != SD_NOT_SCHEDULED,
 779               "SimDag error: Cannot have a watch point for state SD_NOT_SCHEDULED");
 780
 781   task->watch_points = task->watch_points & ~state;
 782   /*  __SD_print_watch_points(task); */
 783 }
 784
 785 /**
 786  * \brief Returns an approximative estimation of the execution time of a task.
 787  *
 788  * The estimation is very approximative because the value returned is the time
 789  * the task would take if it was executed now and if it was the only task.
 790  *
 791  * \param task the task to evaluate
 792  * \param workstation_nb number of workstations on which the task would be executed
 793  * \param workstation_list the workstations on which the task would be executed
 794  * \param computation_amount computation amount for each workstation
 795  * \param communication_amount communication amount between each pair of workstations
 796  * \see SD_schedule()
 797  */
 798 double SD_task_get_execution_time(SD_task_t task,
 799                                   int workstation_nb,
 800                                   const SD_workstation_t *
 801                                   workstation_list,
 802                                   const double *computation_amount,
 803                                   const double *communication_amount)
 804 {
 805   double time, max_time = 0.0;
 806   int i, j;
 807   xbt_assert(workstation_nb > 0, "Invalid parameter");
 808
 809   /* the task execution time is the maximum execution time of the parallel tasks */
 810
 811   for (i = 0; i < workstation_nb; i++) {
 812     time = 0.0;
 813     if (computation_amount != NULL)
 814       time =
 815           SD_workstation_get_computation_time(workstation_list[i],
 816                                               computation_amount[i]);
 817
 818     if (communication_amount != NULL)
 819       for (j = 0; j < workstation_nb; j++) {
 820         time +=
 821             SD_route_get_communication_time(workstation_list[i],
 822                                             workstation_list[j],
 823                                             communication_amount[i *
 824                                                                  workstation_nb
 825                                                                  + j]);
 826       }
 827
 828     if (time > max_time) {
 829       max_time = time;
 830     }
 831   }
 832   return max_time;
 833 }
 834
 835 static XBT_INLINE void SD_task_do_schedule(SD_task_t task)
 836 {
 837   if (!__SD_task_is_not_scheduled(task) && !__SD_task_is_schedulable(task))
 838     THROWF(arg_error, 0, "Task '%s' has already been scheduled",
 839            SD_task_get_name(task));
 840
 841   /* update the task state */
 842   if (task->unsatisfied_dependencies == 0)
 843     __SD_task_set_state(task, SD_RUNNABLE);
 844   else
 845     __SD_task_set_state(task, SD_SCHEDULED);
 846 }
 847
 848 /**
 849  * \brief Schedules a task
 850  *
 851  * The task state must be #SD_NOT_SCHEDULED.
 852  * Once scheduled, a task will be executed as soon as possible in SD_simulate(),
 853  * i.e. when its dependencies are satisfied.
 854  *
 855  * \param task the task you want to schedule
 856  * \param workstation_count number of workstations on which the task will be executed
 857  * \param workstation_list the workstations on which the task will be executed
 858  * \param computation_amount computation amount for each workstation
 859  * \param communication_amount communication amount between each pair of workstations
 860  * \param rate task execution speed rate
 861  * \see SD_task_unschedule()
 862  */
 863 void SD_task_schedule(SD_task_t task, int workstation_count,
 864                       const SD_workstation_t * workstation_list,
 865                       const double *computation_amount,
 866                       const double *communication_amount, double rate)
 867 {
 868   int communication_nb;
 869   task->workstation_nb = 0;
 870   task->rate = -1;
 871   xbt_assert(workstation_count > 0, "workstation_nb must be positive");
 872
 873   task->workstation_nb = workstation_count;
 874   task->rate = rate;
 875
 876   if (computation_amount) {
 877     task->computation_amount = xbt_realloc(task->computation_amount,
 878                                            sizeof(double) * workstation_count);
 879     memcpy(task->computation_amount, computation_amount,
 880            sizeof(double) * workstation_count);
 881   } else {
 882     xbt_free(task->computation_amount);
 883     task->computation_amount = NULL;
 884   }
 885
 886   communication_nb = workstation_count * workstation_count;
 887   if (communication_amount) {
 888     task->communication_amount = xbt_realloc(task->communication_amount,
 889                                              sizeof(double) * communication_nb);
 890     memcpy(task->communication_amount, communication_amount,
 891            sizeof(double) * communication_nb);
 892   } else {
 893     xbt_free(task->communication_amount);
 894     task->communication_amount = NULL;
 895   }
 896
 897   task->workstation_list =
 898     xbt_realloc(task->workstation_list,
 899                 sizeof(SD_workstation_t) * workstation_count);
 900   memcpy(task->workstation_list, workstation_list,
 901          sizeof(SD_workstation_t) * workstation_count);
 902
 903   SD_task_do_schedule(task);
 904 }
 905
 906 /**
 907  * \brief Unschedules a task
 908  *
 909  * The task state must be #SD_SCHEDULED, #SD_RUNNABLE, #SD_RUNNING or #SD_FAILED.
 910  * If you call this function, the task state becomes #SD_NOT_SCHEDULED.
 911  * Call SD_task_schedule() to schedule it again.
 912  *
 913  * \param task the task you want to unschedule
 914  * \see SD_task_schedule()
 915  */
 916 void SD_task_unschedule(SD_task_t task)
 917 {
 918   if (task->state_set != sd_global->scheduled_task_set &&
 919       task->state_set != sd_global->runnable_task_set &&
 920       task->state_set != sd_global->running_task_set &&
 921       task->state_set != sd_global->failed_task_set)
 922     THROWF(arg_error, 0,
 923            "Task %s: the state must be SD_SCHEDULED, SD_RUNNABLE, SD_RUNNING or SD_FAILED",
 924            SD_task_get_name(task));
 925
 926   if (__SD_task_is_scheduled_or_runnable(task)  /* if the task is scheduled or runnable */
 927       &&task->kind == SD_TASK_NOT_TYPED)        /* Don't free scheduling data for typed tasks */
 928     __SD_task_destroy_scheduling_data(task);
 929
 930   if (__SD_task_is_running(task))       /* the task should become SD_FAILED */
 931     surf_workstation_model->action_cancel(task->surf_action);
 932   else {
 933     if (task->unsatisfied_dependencies == 0)
 934       __SD_task_set_state(task, SD_SCHEDULABLE);
 935     else
 936       __SD_task_set_state(task, SD_NOT_SCHEDULED);
 937   }
 938   task->remains = task->amount;
 939   task->start_time = -1.0;
 940 }
 941
 942 /* Destroys the data memorized by SD_task_schedule. Task state must be SD_SCHEDULED or SD_RUNNABLE.
 943  */
 944 static void __SD_task_destroy_scheduling_data(SD_task_t task)
 945 {
 946   if (!__SD_task_is_scheduled_or_runnable(task)
 947       && !__SD_task_is_in_fifo(task))
 948     THROWF(arg_error, 0,
 949            "Task '%s' must be SD_SCHEDULED, SD_RUNNABLE or SD_IN_FIFO",
 950            SD_task_get_name(task));
 951
 952   xbt_free(task->computation_amount);
 953   xbt_free(task->communication_amount);
 954   task->computation_amount = task->communication_amount = NULL;
 955 }
 956
 957 /* Runs a task. This function is directly called by __SD_task_try_to_run if the task
 958  * doesn't have to wait in fifos. Otherwise, it is called by __SD_task_just_done when
 959  * the task gets out of its fifos.
 960  */
 961 void __SD_task_really_run(SD_task_t task)
 962 {
 963
 964   int i;
 965   void **surf_workstations;
 966
 967   xbt_assert(__SD_task_is_runnable_or_in_fifo(task),
 968               "Task '%s' is not runnable or in a fifo! Task state: %d",
 969              SD_task_get_name(task), (int)SD_task_get_state(task));
 970   xbt_assert(task->workstation_list != NULL,
 971               "Task '%s': workstation_list is NULL!",
 972               SD_task_get_name(task));
 973
 974
 975
 976   XBT_DEBUG("Really running task '%s'", SD_task_get_name(task));
 977
 978   /* set this task as current task for the workstations in sequential mode */
 979   for (i = 0; i < task->workstation_nb; i++) {
 980     if (SD_workstation_get_access_mode(task->workstation_list[i]) ==
 981         SD_WORKSTATION_SEQUENTIAL_ACCESS) {
 982       task->workstation_list[i]->current_task = task;
 983       xbt_assert(__SD_workstation_is_busy(task->workstation_list[i]),
 984                   "The workstation should be busy now");
 985     }
 986   }
 987
 988   XBT_DEBUG("Task '%s' set as current task for its workstations",
 989          SD_task_get_name(task));
 990
 991   /* start the task */
 992
 993   /* we have to create a Surf workstation array instead of the SimDag workstation array */
 994   surf_workstations = xbt_new(void *, task->workstation_nb);
 995
 996   for (i = 0; i < task->workstation_nb; i++)
 997     surf_workstations[i] = task->workstation_list[i]->surf_workstation;
 998
 999   /* It's allowed to pass a NULL vector as cost to mean vector of 0.0 (easing user's life). Let's deal with it */
1000 #define cost_or_zero(array,pos) ((array)?(array)[pos]:0.0)
1001
1002   task->surf_action = NULL;
1003   if ((task->workstation_nb == 1)
1004       && (cost_or_zero(task->communication_amount, 0) == 0.0)) {
1005     task->surf_action =
1006         surf_workstation_model->extension.
1007         workstation.execute(surf_workstations[0],
1008                             cost_or_zero(task->computation_amount, 0));
1009   } else if ((task->workstation_nb == 1)
1010              && (cost_or_zero(task->computation_amount, 0) == 0.0)) {
1011
1012     task->surf_action =
1013         surf_workstation_model->extension.
1014         workstation.communicate(surf_workstations[0], surf_workstations[0],
1015                                 cost_or_zero(task->communication_amount,
1016                                              0), task->rate);
1017   } else if ((task->workstation_nb == 2)
1018              && (cost_or_zero(task->computation_amount, 0) == 0.0)
1019              && (cost_or_zero(task->computation_amount, 1) == 0.0)) {
1020     int nb = 0;
1021     double value = 0.0;
1022
1023     for (i = 0; i < task->workstation_nb * task->workstation_nb; i++) {
1024       if (cost_or_zero(task->communication_amount, i) > 0.0) {
1025         nb++;
1026         value = cost_or_zero(task->communication_amount, i);
1027       }
1028     }
1029     if (nb == 1) {
1030       task->surf_action =
1031           surf_workstation_model->extension.
1032           workstation.communicate(surf_workstations[0],
1033                                   surf_workstations[1], value, task->rate);
1034     }
1035   }
1036 #undef cost_or_zero
1037
1038   if (!task->surf_action) {
1039     double *computation_amount = xbt_new(double, task->workstation_nb);
1040     double *communication_amount = xbt_new(double, task->workstation_nb *
1041                                            task->workstation_nb);
1042
1043     memcpy(computation_amount, task->computation_amount, sizeof(double) *
1044            task->workstation_nb);
1045     memcpy(communication_amount, task->communication_amount,
1046            sizeof(double) * task->workstation_nb * task->workstation_nb);
1047
1048     task->surf_action =
1049         surf_workstation_model->extension.
1050         workstation.execute_parallel_task(task->workstation_nb,
1051                                           surf_workstations,
1052                                           computation_amount,
1053                                           communication_amount,
1054                                           task->rate);
1055   } else {
1056     xbt_free(surf_workstations);
1057   }
1058
1059   surf_workstation_model->action_data_set(task->surf_action, task);
1060
1061   XBT_DEBUG("surf_action = %p", task->surf_action);
1062
1063 #ifdef HAVE_TRACING
1064   if (task->category)
1065     TRACE_surf_action(task->surf_action, task->category);
1066 #endif
1067
1068   __SD_task_destroy_scheduling_data(task);      /* now the scheduling data are not useful anymore */
1069   __SD_task_set_state(task, SD_RUNNING);
1070   xbt_assert(__SD_task_is_running(task), "Bad state of task '%s': %d",
1071              SD_task_get_name(task), (int)SD_task_get_state(task));
1072
1073 }
1074
1075 /* Tries to run a task. This function is called by SD_simulate() when a scheduled task becomes SD_RUNNABLE
1076  * (ie when its dependencies are satisfied).
1077  * If one of the workstations where the task is scheduled on is busy (in sequential mode),
1078  * the task doesn't start.
1079  * Returns whether the task has started.
1080  */
1081 int __SD_task_try_to_run(SD_task_t task)
1082 {
1083
1084   int can_start = 1;
1085   int i;
1086   SD_workstation_t workstation;
1087
1088   xbt_assert(__SD_task_is_runnable(task),
1089               "Task '%s' is not runnable! Task state: %d",
1090              SD_task_get_name(task), (int)SD_task_get_state(task));
1091
1092
1093   for (i = 0; i < task->workstation_nb; i++) {
1094     can_start = can_start &&
1095         !__SD_workstation_is_busy(task->workstation_list[i]);
1096   }
1097
1098   XBT_DEBUG("Task '%s' can start: %d", SD_task_get_name(task), can_start);
1099
1100   if (!can_start) {             /* if the task cannot start and is not in the fifos yet */
1101     for (i = 0; i < task->workstation_nb; i++) {
1102       workstation = task->workstation_list[i];
1103       if (workstation->access_mode == SD_WORKSTATION_SEQUENTIAL_ACCESS) {
1104         XBT_DEBUG("Pushing task '%s' in the fifo of workstation '%s'",
1105                SD_task_get_name(task),
1106                SD_workstation_get_name(workstation));
1107         xbt_fifo_push(workstation->task_fifo, task);
1108       }
1109     }
1110     __SD_task_set_state(task, SD_IN_FIFO);
1111     xbt_assert(__SD_task_is_in_fifo(task), "Bad state of task '%s': %d",
1112                SD_task_get_name(task), (int)SD_task_get_state(task));
1113     XBT_DEBUG("Task '%s' state is now SD_IN_FIFO", SD_task_get_name(task));
1114   } else {
1115     __SD_task_really_run(task);
1116   }
1117
1118   return can_start;
1119 }
1120
1121 /* This function is called by SD_simulate when a task is done.
1122  * It updates task->state and task->action and executes if necessary the tasks
1123  * which were waiting in fifos for the end of `task'
1124  */
1125 void __SD_task_just_done(SD_task_t task)
1126 {
1127   int i, j;
1128   SD_workstation_t workstation;
1129
1130   SD_task_t candidate;
1131   int candidate_nb = 0;
1132   int candidate_capacity = 8;
1133   SD_task_t *candidates;
1134   int can_start = 1;
1135
1136   xbt_assert(__SD_task_is_running(task),
1137               "The task must be running! Task state: %d",
1138               (int)SD_task_get_state(task));
1139   xbt_assert(task->workstation_list != NULL,
1140               "Task '%s': workstation_list is NULL!",
1141               SD_task_get_name(task));
1142
1143
1144   candidates = xbt_new(SD_task_t, 8);
1145
1146   __SD_task_set_state(task, SD_DONE);
1147   surf_workstation_model->action_unref(task->surf_action);
1148   task->surf_action = NULL;
1149
1150   XBT_DEBUG("Looking for candidates");
1151
1152   /* if the task was executed on sequential workstations,
1153      maybe we can execute the next task of the fifo for each workstation */
1154   for (i = 0; i < task->workstation_nb; i++) {
1155     workstation = task->workstation_list[i];
1156     XBT_DEBUG("Workstation '%s': access_mode = %d",
1157               SD_workstation_get_name(workstation), (int)workstation->access_mode);
1158     if (workstation->access_mode == SD_WORKSTATION_SEQUENTIAL_ACCESS) {
1159       xbt_assert(workstation->task_fifo != NULL,
1160                   "Workstation '%s' has sequential access but no fifo!",
1161                   SD_workstation_get_name(workstation));
1162       xbt_assert(workstation->current_task =
1163                   task, "Workstation '%s': current task should be '%s'",
1164                   SD_workstation_get_name(workstation),
1165                   SD_task_get_name(task));
1166
1167       /* the task is over so we can release the workstation */
1168       workstation->current_task = NULL;
1169
1170       XBT_DEBUG("Getting candidate in fifo");
1171       candidate =
1172           xbt_fifo_get_item_content(xbt_fifo_get_first_item
1173                                     (workstation->task_fifo));
1174
1175       if (candidate != NULL) {
1176         XBT_DEBUG("Candidate: '%s'", SD_task_get_name(candidate));
1177         xbt_assert(__SD_task_is_in_fifo(candidate),
1178                     "Bad state of candidate '%s': %d",
1179                     SD_task_get_name(candidate),
1180                     (int)SD_task_get_state(candidate));
1181       }
1182
1183       XBT_DEBUG("Candidate in fifo: %p", candidate);
1184
1185       /* if there was a task waiting for my place */
1186       if (candidate != NULL) {
1187         /* Unfortunately, we are not sure yet that we can execute the task now,
1188            because the task can be waiting more deeply in some other workstation's fifos...
1189            So we memorize all candidate tasks, and then we will check for each candidate
1190            whether or not all its workstations are available. */
1191
1192         /* realloc if necessary */
1193         if (candidate_nb == candidate_capacity) {
1194           candidate_capacity *= 2;
1195           candidates =
1196               xbt_realloc(candidates,
1197                           sizeof(SD_task_t) * candidate_capacity);
1198         }
1199
1200         /* register the candidate */
1201         candidates[candidate_nb++] = candidate;
1202         candidate->fifo_checked = 0;
1203       }
1204     }
1205   }
1206
1207   XBT_DEBUG("Candidates found: %d", candidate_nb);
1208
1209   /* now we check every candidate task */
1210   for (i = 0; i < candidate_nb; i++) {
1211     candidate = candidates[i];
1212
1213     if (candidate->fifo_checked) {
1214       continue;                 /* we have already evaluated that task */
1215     }
1216
1217     xbt_assert(__SD_task_is_in_fifo(candidate),
1218                 "Bad state of candidate '%s': %d",
1219                SD_task_get_name(candidate), (int)SD_task_get_state(candidate));
1220
1221     for (j = 0; j < candidate->workstation_nb && can_start; j++) {
1222       workstation = candidate->workstation_list[j];
1223
1224       /* I can start on this workstation if the workstation is shared
1225          or if I am the first task in the fifo */
1226       can_start = workstation->access_mode == SD_WORKSTATION_SHARED_ACCESS
1227           || candidate ==
1228           xbt_fifo_get_item_content(xbt_fifo_get_first_item
1229                                     (workstation->task_fifo));
1230     }
1231
1232     XBT_DEBUG("Candidate '%s' can start: %d", SD_task_get_name(candidate),
1233            can_start);
1234
1235     /* now we are sure that I can start! */
1236     if (can_start) {
1237       for (j = 0; j < candidate->workstation_nb && can_start; j++) {
1238         workstation = candidate->workstation_list[j];
1239
1240         /* update the fifo */
1241         if (workstation->access_mode == SD_WORKSTATION_SEQUENTIAL_ACCESS) {
1242           candidate = xbt_fifo_shift(workstation->task_fifo);   /* the return value is stored just for debugging */
1243           XBT_DEBUG("Head of the fifo: '%s'",
1244                  (candidate !=
1245                   NULL) ? SD_task_get_name(candidate) : "NULL");
1246           xbt_assert(candidate == candidates[i],
1247                       "Error in __SD_task_just_done: bad first task in the fifo");
1248         }
1249       }                         /* for each workstation */
1250
1251       /* finally execute the task */
1252       XBT_DEBUG("Task '%s' state: %d", SD_task_get_name(candidate),
1253              (int)SD_task_get_state(candidate));
1254       __SD_task_really_run(candidate);
1255
1256       XBT_DEBUG
1257           ("Calling __SD_task_is_running: task '%s', state set: %p, running_task_set: %p, is running: %d",
1258            SD_task_get_name(candidate), candidate->state_set,
1259            sd_global->running_task_set, __SD_task_is_running(candidate));
1260       xbt_assert(__SD_task_is_running(candidate),
1261                   "Bad state of task '%s': %d",
1262                   SD_task_get_name(candidate),
1263                  (int)SD_task_get_state(candidate));
1264       XBT_DEBUG("Okay, the task is running.");
1265
1266     }                           /* can start */
1267     candidate->fifo_checked = 1;
1268   }                             /* for each candidate */
1269
1270   xbt_free(candidates);
1271 }
1272
1273 /* Remove all dependencies associated with a task. This function is called when the task is destroyed.
1274  */
1275 static void __SD_task_remove_dependencies(SD_task_t task)
1276 {
1277   /* we must destroy the dependencies carefuly (with SD_dependency_remove)
1278      because each one is stored twice */
1279   SD_dependency_t dependency;
1280   while (!xbt_dynar_is_empty(task->tasks_before)) {
1281     xbt_dynar_get_cpy(task->tasks_before, 0, &dependency);
1282     SD_task_dependency_remove(dependency->src, dependency->dst);
1283   }
1284
1285   while (!xbt_dynar_is_empty(task->tasks_after)) {
1286     xbt_dynar_get_cpy(task->tasks_after, 0, &dependency);
1287     SD_task_dependency_remove(dependency->src, dependency->dst);
1288   }
1289 }
1290
1291 /**
1292  * \brief Returns the start time of a task
1293  *
1294  * The task state must be SD_RUNNING, SD_DONE or SD_FAILED.
1295  *
1296  * \param task: a task
1297  * \return the start time of this task
1298  */
1299 double SD_task_get_start_time(SD_task_t task)
1300 {
1301   if (task->surf_action)
1302     return surf_workstation_model->
1303         action_get_start_time(task->surf_action);
1304   else
1305     return task->start_time;
1306 }
1307
1308 /**
1309  * \brief Returns the finish time of a task
1310  *
1311  * The task state must be SD_RUNNING, SD_DONE or SD_FAILED.
1312  * If the state is not completed yet, the returned value is an
1313  * estimation of the task finish time. This value can fluctuate
1314  * until the task is completed.
1315  *
1316  * \param task: a task
1317  * \return the start time of this task
1318  */
1319 double SD_task_get_finish_time(SD_task_t task)
1320 {
1321   if (task->surf_action)        /* should never happen as actions are destroyed right after their completion */
1322     return surf_workstation_model->
1323         action_get_finish_time(task->surf_action);
1324   else
1325     return task->finish_time;
1326 }
1327 /** @brief Blah
1328  *
1329  */
1330 void SD_task_distribute_comp_amdhal(SD_task_t task, int ws_count)
1331 {
1332   int i;
1333   xbt_assert(task->kind == SD_TASK_COMP_PAR_AMDAHL,
1334               "Task %s is not a SD_TASK_COMP_PAR_AMDAHL typed task."
1335               "Cannot use this function.",
1336               SD_task_get_name(task));
1337
1338   task->computation_amount = xbt_new0(double, ws_count);
1339   task->communication_amount = xbt_new0(double, ws_count * ws_count);
1340   task->workstation_nb = ws_count;
1341   task->workstation_list = xbt_new0(SD_workstation_t, ws_count);
1342
1343   for(i=0;i<ws_count;i++){
1344     task->computation_amount[i] =
1345         (task->alpha + (1 - task->alpha)/ws_count) * task->amount;
1346   }
1347 }
1348
1349 /** @brief Auto-schedules a task.
1350  *
1351  * Auto-scheduling mean that the task can be used with SD_task_schedulev(). This
1352  * allows to specify the task costs at creation, and decorelate them from the
1353  * scheduling process where you just specify which resource should deliver the
1354  * mandatory power.
1355  *
1356  * To be auto-schedulable, a task must be created with SD_task_create_comm_e2e() or
1357  * SD_task_create_comp_seq(). Check their definitions for the exact semantic of each
1358  * of them.
1359  *
1360  * @todo
1361  * We should create tasks kind for the following categories:
1362  *  - Point to point communication (done)
1363  *  - Sequential computation       (done)
1364  *  - group communication (redistribution, several kinds)
1365  *  - parallel tasks with no internal communication (one kind per speedup model such as amdal)
1366  *  - idem+ internal communication. Task type not enough since we cannot store comm cost alongside to comp one)
1367  */
1368 void SD_task_schedulev(SD_task_t task, int count,
1369                        const SD_workstation_t * list)
1370 {
1371   int i;
1372   SD_dependency_t dep;
1373   unsigned int cpt;
1374   xbt_assert(task->kind != 0,
1375               "Task %s is not typed. Cannot automatically schedule it.",
1376               SD_task_get_name(task));
1377   switch (task->kind) {
1378   case SD_TASK_COMM_E2E:
1379   case SD_TASK_COMP_PAR_AMDAHL:
1380     xbt_assert(task->computation_amount, "SD_task_distribute_comp_amdhal should be called first.");
1381   case SD_TASK_COMP_SEQ:
1382     xbt_assert(task->workstation_nb == count,"Got %d locations, but were expecting %d locations",count,task->workstation_nb);
1383     for (i = 0; i < count; i++)
1384       task->workstation_list[i] = list[i];
1385     SD_task_do_schedule(task);
1386     break;
1387   default:
1388     xbt_die("Kind of task %s not supported by SD_task_schedulev()",
1389             SD_task_get_name(task));
1390   }
1391   if (task->kind == SD_TASK_COMM_E2E) {
1392     XBT_VERB("Schedule comm task %s between %s -> %s. It costs %.f bytes",
1393           SD_task_get_name(task),
1394           SD_workstation_get_name(task->workstation_list[0]),
1395           SD_workstation_get_name(task->workstation_list[1]),
1396           task->communication_amount[2]);
1397
1398   }
1399  if (task->kind == SD_TASK_COMP_PAR_AMDAHL) {
1400           XBT_VERB("Schedule computation task %s on %d hosts. It costs %.f flops on each host",
1401             SD_task_get_name(task),
1402                 task->workstation_nb,
1403                 task->computation_amount[0]);
1404  }
1405
1406   /* Iterate over all childs and parent being COMM_E2E to say where I am located (and start them if runnable) */
1407   if (task->kind == SD_TASK_COMP_SEQ) {
1408     XBT_VERB("Schedule computation task %s on %s. It costs %.f flops",
1409           SD_task_get_name(task),
1410           SD_workstation_get_name(task->workstation_list[0]),
1411           task->computation_amount[0]);
1412
1413     xbt_dynar_foreach(task->tasks_before, cpt, dep) {
1414       SD_task_t before = dep->src;
1415       if (before->kind == SD_TASK_COMM_E2E) {
1416         before->workstation_list[1] = task->workstation_list[0];
1417
1418         if (before->workstation_list[0] &&
1419             (__SD_task_is_schedulable(before)
1420              || __SD_task_is_not_scheduled(before))) {
1421           SD_task_do_schedule(before);
1422           XBT_VERB
1423               ("Auto-Schedule comm task %s between %s -> %s. It costs %.f bytes",
1424                SD_task_get_name(before),
1425                SD_workstation_get_name(before->workstation_list[0]),
1426                SD_workstation_get_name(before->workstation_list[1]),
1427                before->communication_amount[2]);
1428         }
1429       }
1430     }
1431     xbt_dynar_foreach(task->tasks_after, cpt, dep) {
1432       SD_task_t after = dep->dst;
1433       if (after->kind == SD_TASK_COMM_E2E) {
1434         after->workstation_list[0] = task->workstation_list[0];
1435         //J-N : Why did you comment on these line (this comment add a bug I think)?
1436         if (after->workstation_list[1]
1437             && (__SD_task_is_not_scheduled(after)
1438                 || __SD_task_is_schedulable(after))) {
1439           SD_task_do_schedule(after);
1440           XBT_VERB
1441               ("Auto-Schedule comm task %s between %s -> %s. It costs %.f bytes",
1442                SD_task_get_name(after),
1443                SD_workstation_get_name(after->workstation_list[0]),
1444                SD_workstation_get_name(after->workstation_list[1]),
1445                after->communication_amount[2]);
1446
1447         }
1448       }
1449     }
1450   }
1451 }
1452
1453 /** @brief autoschedule a task on a list of workstations
1454  *
1455  * This function is very similar to SD_task_schedulev(),
1456  * but takes the list of workstations to schedule onto as separate parameters.
1457  * It builds a proper vector of workstations and then call SD_task_schedulev()
1458  */
1459 void SD_task_schedulel(SD_task_t task, int count, ...)
1460 {
1461   va_list ap;
1462   SD_workstation_t *list = xbt_new(SD_workstation_t, count);
1463   int i;
1464   va_start(ap, count);
1465   for (i = 0; i < count; i++) {
1466     list[i] = va_arg(ap, SD_workstation_t);
1467   }
1468   va_end(ap);
1469   SD_task_schedulev(task, count, list);
1470   free(list);
1471 }
1472
1473 /**
1474  * \brief Sets the tracing category of a task.
1475  *
1476  * This function should be called after the creation of a
1477  * SimDAG task, to define the category of that task. The first
1478  * parameter must contain a task that was created with the
1479  * function #SD_task_create. The second parameter must contain
1480  * a category that was previously declared with the function
1481  * #TRACE_category.
1482  *
1483  * \param task The task to be considered
1484  * \param category the name of the category to be associated to the task
1485  *
1486  * \see SD_task_get_category, TRACE_category, TRACE_category_with_color
1487  */
1488 void SD_task_set_category (SD_task_t task, const char *category)
1489 {
1490 #ifdef HAVE_TRACING
1491   if (!TRACE_is_enabled()) return;
1492   if (task == NULL) return;
1493   if (category == NULL){
1494     if (task->category) xbt_free (task->category);
1495     task->category = NULL;
1496   }else{
1497     task->category = xbt_strdup (category);
1498   }
1499 #endif
1500 }
1501
1502 /**
1503  * \brief Gets the current tracing category of a task.
1504  *
1505  * \param task The task to be considered
1506  *
1507  * \see SD_task_set_category
1508  *
1509  * \return Returns the name of the tracing category of the given task, NULL otherwise
1510  */
1511 const char *SD_task_get_category (SD_task_t task)
1512 {
1513 #ifdef HAVE_TRACING
1514   return task->category;
1515 #else
1516   return NULL;
1517 #endif
1518 }