Add a state SD_READY to the tasks to optimize SD_simulate

git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/simgrid/simgrid/trunk@2452 48e7efb5-ca39-0410-a469-dd3cf9ba447f

diff --git a/examples/simdag/sd_test.c b/examples/simdag/sd_test.c
index 0d901b4..05cc670 100644 (file)
--- a/examples/simdag/sd_test.c
+++ b/examples/simdag/sd_test.c
@@ -31,39 +31,6 @@ int main(int argc, char **argv) {
   SD_task_dependency_add(NULL, NULL, taskD, taskC);
   /*  SD_task_dependency_add(NULL, NULL, taskA, taskD); /\* deadlock */
 
-/*   xbt_ex_t ex; */
-
-/*   TRY { */
-/*     SD_task_dependency_add(NULL, NULL, taskA, taskA); /\* shouldn't work and must raise an exception *\/ */
-/*     xbt_assert0(0, "Hey, I can add a dependency between Task A and Task A!"); */
-/*   } */
-/*   CATCH (ex) { */
-/*   } */
-  
-/*   TRY { */
-/*     SD_task_dependency_add(NULL, NULL, taskA, taskB); /\* shouldn't work and must raise an exception *\/ */
-/*     xbt_assert0(0, "Oh oh, I can add an already existing dependency!"); */
-/*   } */
-/*   CATCH (ex) { */
-/*   } */
-
-/*   SD_task_dependency_remove(taskA, taskB); */
-
-/*   TRY { */
-/*     SD_task_dependency_remove(taskC, taskA); /\* shouldn't work and must raise an exception *\/ */
-/*     xbt_assert0(0, "Dude, I can remove an unknown dependency!"); */
-/*   } */
-/*   CATCH (ex) { */
-/*   } */
-
-/*   TRY { */
-/*     SD_task_dependency_remove(taskC, taskC); /\* shouldn't work and must raise an exception *\/ */
-/*     xbt_assert0(0, "Wow, I can remove a dependency between Task C and itself!"); */
-/*   } */
-/*   CATCH (ex) { */
-/*   } */
-
-
   /* if everything is ok, no exception is forwarded or rethrown by main() */
 
   /* watch points */

diff --git a/src/simdag/private.h b/src/simdag/private.h
index eafc778..d826d3a 100644 (file)
--- a/src/simdag/private.h
+++ b/src/simdag/private.h
@@ -20,6 +20,7 @@ typedef struct SD_global {
   /* task state sets */
   xbt_swag_t not_scheduled_task_set;
   xbt_swag_t scheduled_task_set;
+  xbt_swag_t ready_task_set;
   xbt_swag_t running_task_set;
   xbt_swag_t done_task_set;
   xbt_swag_t failed_task_set;
@@ -49,7 +50,8 @@ typedef struct SD_task {
   double amount;
   surf_action_t surf_action;
   unsigned short watch_points;
-  int state_changed;
+  int state_changed; /* used only by SD_simulate, to make sure we put
+                       the task only once in the returning array */
 
   /* dependencies */
   xbt_dynar_t tasks_before;
@@ -84,4 +86,34 @@ void __SD_task_set_state(SD_task_t task, e_SD_task_state_t new_state);
 surf_action_t __SD_task_run(SD_task_t task);
 void __SD_task_remove_dependencies(SD_task_t task);
 
+/* Functions to test if the task is in a given state.
+   These functions are faster than using SD_task_get_state() */
+
+/* Returns whether the given task is scheduled or ready. */
+static _XBT_INLINE int __SD_task_is_scheduled_or_ready(SD_task_t task) {
+  return task->state_set == sd_global->scheduled_task_set ||
+    task->state_set == sd_global->ready_task_set;
+}
+
+/* Returns whether the state of the given task is SD_NOT_SCHEDULED. */
+static _XBT_INLINE int __SD_task_is_not_scheduled(SD_task_t task) {
+  return task->state_set == sd_global->not_scheduled_task_set;
+}
+
+/* Returns whether the state of the given task is SD_SCHEDULED. */
+static _XBT_INLINE int __SD_task_is_scheduled(SD_task_t task) {
+  return task->state_set == sd_global->scheduled_task_set;
+}
+
+/* Returns whether the state of the given task is SD_READY. */
+static _XBT_INLINE int __SD_task_is_ready(SD_task_t task) {
+  return task->state_set == sd_global->ready_task_set;
+}
+
+/* Returns whether the state of the given task is SD_RUNNING. */
+static _XBT_INLINE int __SD_task_is_running(SD_task_t task) {
+  return task->state_set == sd_global->running_task_set;
+}
+
+
 #endif

diff --git a/src/simdag/sd_global.c b/src/simdag/sd_global.c
index e3bf318..576c163 100644 (file)
--- a/src/simdag/sd_global.c
+++ b/src/simdag/sd_global.c
@@ -23,6 +23,7 @@ void SD_init(int *argc, char **argv) {
   s_SD_task_t task;
   sd_global->not_scheduled_task_set = xbt_swag_new(xbt_swag_offset(task, state_hookup));
   sd_global->scheduled_task_set = xbt_swag_new(xbt_swag_offset(task, state_hookup));
+  sd_global->ready_task_set = xbt_swag_new(xbt_swag_offset(task, state_hookup));
   sd_global->running_task_set = xbt_swag_new(xbt_swag_offset(task, state_hookup));
   sd_global->done_task_set = xbt_swag_new(xbt_swag_offset(task, state_hookup));
   sd_global->failed_task_set = xbt_swag_new(xbt_swag_offset(task, state_hookup));
@@ -67,18 +68,16 @@ void SD_create_environment(const char *platform_file) {
  */
 SD_task_t* SD_simulate(double how_long)
 {
-  /* TODO */
-
   double total_time = 0.0; /* we stop the simulation when total_time >= how_long */
   double elapsed_time = 0.0;
   SD_task_t task;
   surf_action_t action;
   SD_task_t *changed_tasks = NULL;
   int changed_task_number = 0;
-  int changed_task_capacity = 16;
+  int changed_task_capacity = 16; /* will be increased if necessary */
 
   /* create the array that will be returned */
-  changed_tasks = xbt_new0(SD_task_t, changed_task_capacity); /* changed_task_capacity will be increased if necessary */
+  changed_tasks = xbt_new0(SD_task_t, changed_task_capacity);
   changed_tasks[0] = NULL;
 
   surf_solve(); /* Takes traces into account. Returns 0.0 */
@@ -88,33 +87,27 @@ SD_task_t* SD_simulate(double how_long)
   /* main loop */
   while (elapsed_time >= 0.0 && total_time < how_long && !sd_global->watch_point_reached) {
 
-    /* explore the scheduled tasks */
-    xbt_swag_foreach(task, sd_global->scheduled_task_set) {
-      INFO1("Examining task '%s'...", SD_task_get_name(task));
+    /* explore the ready tasks */
+    xbt_swag_foreach(task, sd_global->ready_task_set) {
+      INFO1("Executing task '%s'", SD_task_get_name(task));
       task->state_changed = 0;
-      if (xbt_dynar_length(task->tasks_before) == 0) {
-       INFO1("The dependencies are satisfied. Executing task '%s'", SD_task_get_name(task));
-       action = __SD_task_run(task);
-       surf_workstation_resource->common_public->action_set_data(action, task);
-       task->state_changed = 1;
-       
-       changed_tasks[changed_task_number++] = task; /* replace NULL by the task */
-       if (changed_task_number == changed_task_capacity) {
-         changed_task_capacity *= 2;
-         changed_tasks = xbt_realloc(changed_tasks, sizeof(SD_task_t) * changed_task_capacity);
-       }
-       changed_tasks[changed_task_number] = NULL;
-      }
-      else {
-       INFO1("Cannot execute task '%s' now because some depencies are not satisfied.", SD_task_get_name(task));
+      action = __SD_task_run(task);
+      surf_workstation_resource->common_public->action_set_data(action, task);
+      task->state_changed = 1;
+      
+      changed_tasks[changed_task_number++] = task; /* replace NULL by the task */
+      if (changed_task_number == changed_task_capacity) {
+       changed_task_capacity *= 2;
+       changed_tasks = xbt_realloc(changed_tasks, sizeof(SD_task_t) * changed_task_capacity);
       }
+      changed_tasks[changed_task_number] = NULL;
     }
 
     elapsed_time = surf_solve();
     if (elapsed_time > 0.0)
       total_time += elapsed_time;
-    /*    INFO1("Total time: %f", total_time);*/
 
+    /* let's see which tasks are done */
     while ((action = xbt_swag_extract(surf_workstation_resource->common_public->states.done_action_set))) {
       task = action->data;
       INFO1("Task '%s' done", SD_task_get_name(task));
@@ -126,6 +119,7 @@ SD_task_t* SD_simulate(double how_long)
       }
     }
 
+    /* let's see which tasks have just failed */
     while ((action = xbt_swag_extract(surf_workstation_resource->common_public->states.failed_action_set))) {
       task = action->data;
       INFO1("Task '%s' failed", SD_task_get_name(task));
@@ -138,8 +132,8 @@ SD_task_t* SD_simulate(double how_long)
   }
 
   INFO0("Simulation finished");
-
   INFO1("Number of tasks whose state has changed: %d", changed_task_number);
+
   return changed_tasks;
 }
 
@@ -154,6 +148,7 @@ void SD_exit(void) {
 
     xbt_swag_free(sd_global->not_scheduled_task_set);
     xbt_swag_free(sd_global->scheduled_task_set);
+    xbt_swag_free(sd_global->ready_task_set);
     xbt_swag_free(sd_global->running_task_set);
     xbt_swag_free(sd_global->done_task_set);
     xbt_swag_free(sd_global->failed_task_set);

diff --git a/src/simdag/sd_task.c b/src/simdag/sd_task.c
index dbafd2b..b534a22 100644 (file)
--- a/src/simdag/sd_task.c
+++ b/src/simdag/sd_task.c
@@ -48,7 +48,7 @@ void* SD_task_get_data(SD_task_t task) {
   return task->data;
 }
 
-/* Returns the state of a task: SD_NOT_SCHEDULED, SD_SCHEDULED, SD_RUNNING, SD_DONE or SD_FAILED.
+/* Returns the state of a task: SD_NOT_SCHEDULED, SD_SCHEDULED, SD_READY, SD_RUNNING, SD_DONE or SD_FAILED.
  */
 e_SD_task_state_t SD_task_get_state(SD_task_t task) {
   SD_CHECK_INIT_DONE();
@@ -58,6 +58,8 @@ e_SD_task_state_t SD_task_get_state(SD_task_t task) {
     return SD_NOT_SCHEDULED;
   if (task->state_set == sd_global->scheduled_task_set)
     return SD_SCHEDULED;
+  if (task->state_set == sd_global->ready_task_set)
+    return SD_READY;
   if (task->state_set == sd_global->running_task_set)
     return SD_RUNNING;
   if (task->state_set == sd_global->done_task_set)
@@ -65,7 +67,7 @@ e_SD_task_state_t SD_task_get_state(SD_task_t task) {
   return SD_FAILED;
 }
 
-/* Changes the state of a task. Update the swags and the flag sd_global->watch_point_reached.
+/* Changes the state of a task. Updates the swags and the flag sd_global->watch_point_reached.
  */
 void __SD_task_set_state(SD_task_t task, e_SD_task_state_t new_state) {
   xbt_swag_remove(task, task->state_set);
@@ -76,6 +78,9 @@ void __SD_task_set_state(SD_task_t task, e_SD_task_state_t new_state) {
   case SD_SCHEDULED:
     task->state_set = sd_global->scheduled_task_set;
     break;
+  case SD_READY:
+    task->state_set = sd_global->ready_task_set;
+    break;
   case SD_RUNNING:
     task->state_set = sd_global->running_task_set;
     break;
@@ -129,8 +134,8 @@ double SD_task_get_remaining_amount(SD_task_t task) {
     return task->surf_action->remains;
 }
 
-/* temporary function for debbuging
-void __SD_print_dependencies(SD_task_t task) {
+/* temporary function for debbuging */
+static void __SD_print_dependencies(SD_task_t task) {
   printf("The following tasks must be executed before %s:", SD_task_get_name(task));
   xbt_dynar_t dynar = task->tasks_before;
   int length = xbt_dynar_length(dynar);
@@ -150,7 +155,7 @@ void __SD_print_dependencies(SD_task_t task) {
     printf(" %s", SD_task_get_name(dependency->dst));
   }
   printf("\n----------------------------\n");
-}*/
+}
 
 /* Destroys a dependency between two tasks.
  */
@@ -160,12 +165,17 @@ static void __SD_task_dependency_destroy(void *dependency) {
   xbt_free(dependency);
 }
 
-/* Adds a dependency between two tasks.
+/* Adds a dependency between two tasks. Their state must be SD_NOT_SCHEDULED, SD_SCHEDULED
+ * or SD_READY.
  */
 void SD_task_dependency_add(const char *name, void *data, SD_task_t src, SD_task_t dst) {
   SD_CHECK_INIT_DONE();
   xbt_assert0(src != NULL && dst != NULL, "Invalid parameter");
   xbt_assert1(src != dst, "Cannot add a dependency between task '%s' and itself", SD_task_get_name(src));
+  xbt_assert1(__SD_task_is_not_scheduled(src) || __SD_task_is_scheduled_or_ready(src),
+             "Task '%s' must be SD_NOT_SCHEDULED, SD_SCHEDULED or SD_READY", SD_task_get_name(src));
+  xbt_assert1(__SD_task_is_not_scheduled(dst) || __SD_task_is_scheduled_or_ready(dst),
+             "Task '%s' must be SD_NOT_SCHEDULED, SD_SCHEDULED or SD_READY", SD_task_get_name(dst));
 
   xbt_dynar_t dynar = src->tasks_after;
   int length = xbt_dynar_length(dynar);
@@ -176,7 +186,8 @@ void SD_task_dependency_add(const char *name, void *data, SD_task_t src, SD_task
     xbt_dynar_get_cpy(dynar, i, &dependency);
     found = (dependency->dst == dst);
   }
-  xbt_assert2(!found, "A dependency already exists between task '%s' and task '%s'", SD_task_get_name(src), SD_task_get_name(dst));
+  xbt_assert2(!found, "A dependency already exists between task '%s' and task '%s'",
+             SD_task_get_name(src), SD_task_get_name(dst));
 
   dependency = xbt_new0(s_SD_dependency_t, 1);
 
@@ -190,6 +201,13 @@ void SD_task_dependency_add(const char *name, void *data, SD_task_t src, SD_task
   xbt_dynar_push(src->tasks_after, &dependency);
   xbt_dynar_push(dst->tasks_before, &dependency);
 
+  /* if the task was ready, then dst->tasks_before is not empty anymore,
+     so we must go back to state SD_SCHEDULED */
+  if (__SD_task_is_ready(dst)) {
+    printf("SD_task_dependency_add: %s was ready and becomes scheduled!\n", SD_task_get_name(dst));
+    __SD_task_set_state(dst, SD_SCHEDULED);
+  }
+
   /*  __SD_print_dependencies(src);
       __SD_print_dependencies(dst); */
 }
@@ -199,8 +217,8 @@ void SD_task_dependency_add(const char *name, void *data, SD_task_t src, SD_task
 void SD_task_dependency_remove(SD_task_t src, SD_task_t dst) {
   SD_CHECK_INIT_DONE();
   xbt_assert0(src != NULL && dst != NULL, "Invalid parameter");
-  xbt_assert1(src != dst, "Cannot remove a dependency between task '%s' and itself", SD_task_get_name(src));
 
+  /* remove the dependency from src->tasks_after */
   xbt_dynar_t dynar = src->tasks_after;
   int length = xbt_dynar_length(dynar);
   int found = 0;
@@ -216,6 +234,7 @@ void SD_task_dependency_remove(SD_task_t src, SD_task_t dst) {
   xbt_assert4(found, "No dependency found between task '%s' and '%s': task '%s' is not a successor of task '%s'",
              SD_task_get_name(src), SD_task_get_name(dst), SD_task_get_name(dst), SD_task_get_name(src));
 
+  /* remove the dependency from dst->tasks_before */
   dynar = dst->tasks_before;
   length = xbt_dynar_length(dynar);
   found = 0;
@@ -231,8 +250,12 @@ void SD_task_dependency_remove(SD_task_t src, SD_task_t dst) {
   xbt_assert4(found, "SimDag error: task '%s' is a successor of '%s' but task '%s' is not a predecessor of task '%s'",
              SD_task_get_name(dst), SD_task_get_name(src), SD_task_get_name(src), SD_task_get_name(dst)); /* should never happen... */
 
-  /*   __SD_print_dependencies(src); 
-       __SD_print_dependencies(dst); */
+  /* if the task was scheduled and dst->tasks_before is empty now, we can make it ready */
+  if (xbt_dynar_length(dst->tasks_before) == 0 && __SD_task_is_scheduled(dst))
+    __SD_task_set_state(dst, SD_READY);
+
+  /*  __SD_print_dependencies(src); 
+      __SD_print_dependencies(dst);*/
 }
 
 /* Returns the data associated to a dependency between two tasks. This data can be NULL.
@@ -240,7 +263,6 @@ void SD_task_dependency_remove(SD_task_t src, SD_task_t dst) {
 void *SD_task_dependency_get_data(SD_task_t src, SD_task_t dst) {
   SD_CHECK_INIT_DONE();
   xbt_assert0(src != NULL && dst != NULL, "Invalid parameter");
-  xbt_assert1(src != dst, "Cannot have a dependency between task '%s' and itself", SD_task_get_name(src));
 
   xbt_dynar_t dynar = src->tasks_after;
   int length = xbt_dynar_length(dynar);
@@ -257,13 +279,13 @@ void *SD_task_dependency_get_data(SD_task_t src, SD_task_t dst) {
 
 /* temporary function for debugging */
 static void __SD_print_watch_points(SD_task_t task) {
-  static const int state_masks[] = {SD_SCHEDULED, SD_RUNNING, SD_DONE, SD_FAILED};
-  static const char* state_names[] = {"scheduled", "running", "done", "failed"};
+  static const int state_masks[] = {SD_SCHEDULED, SD_RUNNING, SD_READY, SD_DONE, SD_FAILED};
+  static const char* state_names[] = {"scheduled", "running", "ready", "done", "failed"};
 
   printf("Task '%s' watch points (%x): ", SD_task_get_name(task), task->watch_points);
 
   int i;
-  for (i = 0; i < 4; i++) {
+  for (i = 0; i < 5; i++) {
     if (task->watch_points & state_masks[i])
       printf("%s ", state_names[i]);
   }
@@ -273,28 +295,35 @@ static void __SD_print_watch_points(SD_task_t task) {
 /* Adds a watch point to a task.
    SD_simulate will stop as soon as the state of this task is the one given in argument.
    Watch point is then automatically removed.
+   The given state must be SD_SCHEDULED, SD_READY, SD_RUNNING, SD_DONE or SD_FAILED.
  */
 void SD_task_watch(SD_task_t task, e_SD_task_state_t state) {
   SD_CHECK_INIT_DONE();
   xbt_assert0(task != NULL, "Invalid parameter");
+  xbt_assert0(state != SD_NOT_SCHEDULED, "Cannot add a watch point for state SD_NOT_SCHEDULED");
 
   task->watch_points = task->watch_points | state;
   __SD_print_watch_points(task);
 }
 
 /* Removes a watch point from a task.
+   The given state must be SD_SCHEDULED, SD_READY, SD_RUNNING, SD_DONE or SD_FAILED.
  */
 void SD_task_unwatch(SD_task_t task, e_SD_task_state_t state) {
   SD_CHECK_INIT_DONE();
   xbt_assert0(task != NULL, "Invalid parameter");
+  xbt_assert0(state != SD_NOT_SCHEDULED, "Cannot have a watch point for state SD_NOT_SCHEDULED");
   
   task->watch_points = task->watch_points & ~state;
   __SD_print_watch_points(task);
 }
 
-/* Destroys the data memorised by SD_task_schedule. Task state must be SD_SCHEDULED.
+/* Destroys the data memorised by SD_task_schedule. Task state must be SD_SCHEDULED or SD_READY.
  */
 static void __SD_task_destroy_scheduling_data(SD_task_t task) {
+  SD_CHECK_INIT_DONE();
+  xbt_assert1(__SD_task_is_scheduled_or_ready(task),
+             "Task '%s' must be SD_SCHEDULED or SD_READY", SD_task_get_name(task));
   xbt_free(task->workstation_list);
   xbt_free(task->computation_amount);
   xbt_free(task->communication_amount);
@@ -313,7 +342,7 @@ void SD_task_schedule(SD_task_t task, int workstation_nb,
                     double *communication_amount, double rate) {
   SD_CHECK_INIT_DONE();
   xbt_assert0(task, "Invalid parameter");
-  xbt_assert1(SD_task_get_state(task) == SD_NOT_SCHEDULED, "Task '%s' has already been scheduled.", SD_task_get_name(task));
+  xbt_assert1(__SD_task_is_not_scheduled(task), "Task '%s' has already been scheduled.", SD_task_get_name(task));
   xbt_assert0(workstation_nb > 0, "workstation_nb must be positive");
 
   task->workstation_nb = workstation_nb;
@@ -333,26 +362,34 @@ void SD_task_schedule(SD_task_t task, int workstation_nb,
     task->workstation_list[i] = workstation_list[i]->surf_workstation;
   }
 
-  __SD_task_set_state(task, SD_SCHEDULED);
+  /* update the task state */
+  if (xbt_dynar_length(task->tasks_before) == 0)
+    __SD_task_set_state(task, SD_READY);
+  else
+    __SD_task_set_state(task, SD_SCHEDULED);
 }
 
-/* Unschedules a task. The state must be SD_SCHEDULED, SD_RUNNING or SD_FAILED.
+/* Unschedules a task. The state must be SD_SCHEDULED, SD_READY, SD_RUNNING or SD_FAILED.
  * The task is reinitialised and its state becomes SD_NOT_SCHEDULED.
  * Call SD_task_schedule to schedule it again.
  */
 void SD_task_unschedule(SD_task_t task) {
   SD_CHECK_INIT_DONE();
   xbt_assert0(task != NULL, "Invalid parameter");
-  e_SD_task_state_t state = SD_task_get_state(task);
-  xbt_assert1(state == SD_SCHEDULED ||
-             state == SD_RUNNING ||
-             state == SD_FAILED,
-             "Task %s: the state must be SD_SCHEDULED, SD_RUNNING or SD_FAILED", SD_task_get_name(task));
-
-  if (state == SD_SCHEDULED)
+  xbt_assert1(task->state_set == sd_global->scheduled_task_set ||
+             task->state_set == sd_global->ready_task_set ||
+             task->state_set == sd_global->running_task_set ||
+             task->state_set == sd_global->failed_task_set,
+             "Task %s: the state must be SD_SCHEDULED, SD_READY, SD_RUNNING or SD_FAILED",
+             SD_task_get_name(task));
+
+  if (__SD_task_is_scheduled_or_ready(task)) /* if the task is scheduled or ready */
     __SD_task_destroy_scheduling_data(task);
 
-  __SD_task_set_state(task, SD_NOT_SCHEDULED);
+  if (__SD_task_is_running(task)) /* the task should become SD_FAILED */
+    surf_workstation_resource->common_public->action_cancel(task->surf_action);
+  else
+    __SD_task_set_state(task, SD_NOT_SCHEDULED);
 }
 
 /* Runs a task. This function is called by SD_simulate when a scheduled task can start
@@ -361,7 +398,8 @@ void SD_task_unschedule(SD_task_t task) {
 surf_action_t __SD_task_run(SD_task_t task) {
   SD_CHECK_INIT_DONE();
   xbt_assert0(task != NULL, "Invalid parameter");
-
+  xbt_assert2(__SD_task_is_ready(task), "Task '%s' is not ready! Task state: %d",
+             SD_task_get_name(task), SD_task_get_state(task));
 
   surf_action_t surf_action = surf_workstation_resource->extension_public->
     execute_parallel_task(task->workstation_nb,
@@ -370,9 +408,10 @@ surf_action_t __SD_task_run(SD_task_t task) {
                          task->communication_amount,
                          task->amount,
                          task->rate);
-  __SD_task_set_state(task, SD_RUNNING);
 
   __SD_task_destroy_scheduling_data(task); /* now the scheduling data are not useful anymore */
+  __SD_task_set_state(task, SD_RUNNING);
+
   return surf_action;
 }
 
@@ -403,8 +442,8 @@ void SD_task_destroy(SD_task_t task) {
 
   __SD_task_remove_dependencies(task);
 
-  /* if the task was scheduled we have to free the scheduling parameters */
-  if (SD_task_get_state(task) == SD_SCHEDULED)
+  /* if the task was scheduled or ready we have to free the scheduling parameters */
+  if (__SD_task_is_scheduled_or_ready(task))
     __SD_task_destroy_scheduling_data(task);
 
   if (task->name != NULL)