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avoid the complilation of dot_test.c if graphviz wasn't found
[simgrid.git] / src / msg / gos.c
index dc30683..943df63 100644 (file)
-/*     $Id$     */
-
-/* Copyright (c) 2002,2003,2004 Arnaud Legrand. All rights reserved.        */
+/* Copyright (c) 2004, 2005, 2006, 2007, 2008, 2009, 2010. The SimGrid Team.
+ * All rights reserved.                                                     */
 
 /* This program is free software; you can redistribute it and/or modify it
  * under the terms of the license (GNU LGPL) which comes with this package. */
 
-#include "private.h"
+#include "msg/private.h"
+#include "simix/private.h"
 #include "xbt/sysdep.h"
+#include "mc/mc.h"
 #include "xbt/log.h"
-XBT_LOG_NEW_DEFAULT_SUBCATEGORY(gos, msg,
-                               "Logging specific to MSG (gos)");
+#include "mailbox.h"
 
-/** \defgroup msg_gos_functions MSG Operating System Functions
- *  \brief This section describes the functions that can be used
- *  by an agent for handling some task.
+
+XBT_LOG_NEW_DEFAULT_SUBCATEGORY(msg_gos, msg,
+               "Logging specific to MSG (gos)");
+
+/** \ingroup msg_gos_functions
+ *
+ * \brief Return the last value returned by a MSG function (except
+ * MSG_get_errno...).
  */
+MSG_error_t MSG_get_errno(void)
+{
+       return PROCESS_GET_ERRNO();
+}
 
-static MSG_error_t __MSG_task_get_with_time_out_from_host(m_task_t * task,
-                                                       m_channel_t channel,
-                                                       double max_duration,
-                                                       m_host_t host)
+/** \ingroup msg_gos_functions
+ * \brief Executes a task and waits for its termination.
+ *
+ * This function is used for describing the behavior of an agent. It
+ * takes only one parameter.
+ * \param task a #m_task_t to execute on the location on which the
+ agent is running.
+ * \return #MSG_FATAL if \a task is not properly initialized and
+ * #MSG_OK otherwise.
+ */
+MSG_error_t MSG_task_execute(m_task_t task)
 {
-  m_process_t process = MSG_process_self();
-  m_task_t t = NULL;
-  m_host_t h = NULL;
-  simdata_task_t t_simdata = NULL;
-  simdata_host_t h_simdata = NULL;
-  int first_time = 1;
-  e_surf_action_state_t state = SURF_ACTION_NOT_IN_THE_SYSTEM;
-  xbt_fifo_item_t item = NULL;
-
-  CHECK_HOST();
-  xbt_assert1((channel>=0) && (channel < msg_global->max_channel),"Invalid channel %d",channel);
-  /* Sanity check */
-  xbt_assert0(task,"Null pointer for the task\n");
-
-  if (*task) 
-    CRITICAL0("MSG_task_get() was asked to write in a non empty task struct.");
-
-  /* Get the task */
-  h = MSG_host_self();
-  h_simdata = h->simdata;
-
-  DEBUG2("Waiting for a task on channel %d (%s)", channel,h->name);
-
-  while (1) {
-    if(xbt_fifo_size(h_simdata->mbox[channel])>0) {
-      if(!host) {
-       t = xbt_fifo_shift(h_simdata->mbox[channel]);
-       break;
-      } else {
-       xbt_fifo_foreach(h->simdata->mbox[channel],item,t,m_task_t) {
-         if(t->simdata->source==host) break;
+       simdata_task_t simdata = NULL;
+       m_process_t self = MSG_process_self();
+       e_surf_action_state_t state = SURF_ACTION_NOT_IN_THE_SYSTEM;
+       CHECK_HOST();
+
+       simdata = task->simdata;
+
+       xbt_assert0(simdata->host_nb==0, "This is a parallel task. Go to hell.");
+
+#ifdef HAVE_TRACING
+       TRACE_msg_task_execute_start (task);
+#endif
+
+       xbt_assert1((!simdata->compute) && (task->simdata->refcount == 1),
+                       "This task is executed somewhere else. Go fix your code! %d", task->simdata->refcount);
+
+       DEBUG1("Computing on %s", MSG_process_self()->simdata->m_host->name);
+
+       if (simdata->computation_amount == 0) {
+#ifdef HAVE_TRACING
+               TRACE_msg_task_execute_end (task);
+#endif
+               return MSG_OK;
+       }
+       simdata->refcount++;
+       SIMIX_mutex_lock(simdata->mutex);
+       simdata->compute =
+               SIMIX_action_execute(SIMIX_host_self(), task->name,
+                               simdata->computation_amount);
+       SIMIX_action_set_priority(simdata->compute, simdata->priority);
+
+       /* changed to waiting action since we are always waiting one action (execute, communicate or sleep) */
+       self->simdata->waiting_action = simdata->compute;
+       SIMIX_register_action_to_condition(simdata->compute, simdata->cond);
+       do {
+               SIMIX_cond_wait(simdata->cond, simdata->mutex);
+               state = SIMIX_action_get_state(simdata->compute);
+       } while (state == SURF_ACTION_READY || state == SURF_ACTION_RUNNING);
+       SIMIX_unregister_action_to_condition(simdata->compute, simdata->cond);
+       self->simdata->waiting_action = NULL;
+
+       SIMIX_mutex_unlock(simdata->mutex);
+       simdata->refcount--;
+
+       if (SIMIX_action_get_state(task->simdata->compute) == SURF_ACTION_DONE) {
+               /* action ended, set comm and compute = NULL, the actions is already destroyed in the main function */
+               SIMIX_action_destroy(task->simdata->compute);
+               simdata->computation_amount = 0.0;
+               simdata->comm = NULL;
+               simdata->compute = NULL;
+#ifdef HAVE_TRACING
+               TRACE_msg_task_execute_end (task);
+#endif
+               MSG_RETURN(MSG_OK);
+       } else if (SIMIX_host_get_state(SIMIX_host_self()) == 0) {
+               /* action ended, set comm and compute = NULL, the actions is already destroyed in the main function */
+               SIMIX_action_destroy(task->simdata->compute);
+               simdata->comm = NULL;
+               simdata->compute = NULL;
+#ifdef HAVE_TRACING
+               TRACE_msg_task_execute_end (task);
+#endif
+               MSG_RETURN(MSG_HOST_FAILURE);
+       } else {
+               /* action ended, set comm and compute = NULL, the actions is already destroyed in the main function */
+               SIMIX_action_destroy(task->simdata->compute);
+               simdata->comm = NULL;
+               simdata->compute = NULL;
+#ifdef HAVE_TRACING
+               TRACE_msg_task_execute_end (task);
+#endif
+               MSG_RETURN(MSG_TASK_CANCELLED);
        }
-       if(item) {
-         xbt_fifo_remove_item(h->simdata->mbox[channel],item);
-         break;
-       } 
-      }
-    }
-                                                      
-    if(max_duration>0) {
-      if(!first_time) {
-       MSG_RETURN(MSG_OK);
-      }
-    }
-    xbt_assert2(!(h_simdata->sleeping[channel]),
-               "A process (%s(%d)) is already blocked on this channel",
-               h_simdata->sleeping[channel]->name,
-               h_simdata->sleeping[channel]->simdata->PID);
-    h_simdata->sleeping[channel] = process; /* I'm waiting. Wake me up when you're ready */
-    if(max_duration>0) {
-      __MSG_process_block(max_duration);
-    } else {
-      __MSG_process_block(-1);
-    }
-    if(surf_workstation_resource->extension_public->get_state(h_simdata->host) 
-       == SURF_CPU_OFF)
-      MSG_RETURN(MSG_HOST_FAILURE);
-    h_simdata->sleeping[channel] = NULL;
-    first_time = 0;
-    /* OK, we should both be ready now. Are you there ? */
-  }
-
-  DEBUG1("OK, got a task (%s)", t->name);
-
-  t_simdata = t->simdata;
-  /*   *task = __MSG_task_copy(t); */
-  *task=t;
-
-  /* Transfer */
-  t_simdata->using++;
-
-  DEBUG0("Calling SURF for communication creation");
-  t_simdata->comm = surf_workstation_resource->extension_public->
-    communicate(MSG_process_get_host(t_simdata->sender)->simdata->host,
-               h->simdata->host, t_simdata->message_size,t_simdata->rate);
-  
-  surf_workstation_resource->common_public->action_set_data(t_simdata->comm,t);
-
-  if(__MSG_process_isBlocked(t_simdata->sender))
-    __MSG_process_unblock(t_simdata->sender);
-
-  PAJE_PROCESS_PUSH_STATE(process,"C");  
-
-  do {
-    DEBUG0("Waiting for action termination");
-    __MSG_task_wait_event(process, t);
-    state=surf_workstation_resource->common_public->action_get_state(t_simdata->comm);
-  } while (state==SURF_ACTION_RUNNING);
-  DEBUG0("Action terminated");
-
-  if(t->simdata->using>1) {
-    xbt_fifo_unshift(msg_global->process_to_run,process);
-    xbt_context_yield();
-  }
-
-  PAJE_PROCESS_POP_STATE(process);
-  PAJE_COMM_STOP(process,t,channel);
-
-  if(state == SURF_ACTION_DONE) {
-    if(surf_workstation_resource->common_public->action_free(t_simdata->comm)) 
-      t_simdata->comm = NULL;
-    MSG_RETURN(MSG_OK);
-  } else if(surf_workstation_resource->extension_public->get_state(h_simdata->host) 
-         == SURF_CPU_OFF) {
-    if(surf_workstation_resource->common_public->action_free(t_simdata->comm)) 
-      t_simdata->comm = NULL;
-    MSG_RETURN(MSG_HOST_FAILURE);
-  } else {
-    if(surf_workstation_resource->common_public->action_free(t_simdata->comm)) 
-      t_simdata->comm = NULL;
-    MSG_RETURN(MSG_TRANSFER_FAILURE);
-  }
 }
 
-/** \ingroup msg_gos_functions
- * \brief Listen on a channel and wait for receiving a task.
+/** \ingroup m_task_management
+ * \brief Creates a new #m_task_t (a parallel one....).
  *
- * It takes two parameters.
- * \param task a memory location for storing a #m_task_t. It will
-   hold a task when this function will return. Thus \a task should not
-   be equal to \c NULL and \a *task should be equal to \c NULL. If one of
-   those two condition does not hold, there will be a warning message.
- * \param channel the channel on which the agent should be
-   listening. This value has to be >=0 and < than the maximal
-   number of channels fixed with MSG_set_channel_number().
- * \return #MSG_FATAL if \a task is equal to \c NULL, #MSG_WARNING
- * if \a *task is not equal to \c NULL, and #MSG_OK otherwise.
+ * A constructor for #m_task_t taking six arguments and returning the
+ corresponding object.
+ * \param name a name for the object. It is for user-level information
+ and can be NULL.
+ * \param host_nb the number of hosts implied in the parallel task.
+ * \param host_list an array of \p host_nb m_host_t.
+ * \param computation_amount an array of \p host_nb
+ doubles. computation_amount[i] is the total number of operations
+ that have to be performed on host_list[i].
+ * \param communication_amount an array of \p host_nb* \p host_nb doubles.
+ * \param data a pointer to any data may want to attach to the new
+ object.  It is for user-level information and can be NULL. It can
+ be retrieved with the function \ref MSG_task_get_data.
+ * \see m_task_t
+ * \return The new corresponding object.
  */
-MSG_error_t MSG_task_get(m_task_t * task,
-                        m_channel_t channel)
+       m_task_t
+MSG_parallel_task_create(const char *name, int host_nb,
+               const m_host_t * host_list,
+               double *computation_amount,
+               double *communication_amount, void *data)
+{
+       int i;
+       simdata_task_t simdata = xbt_new0(s_simdata_task_t, 1);
+       m_task_t task = xbt_new0(s_m_task_t, 1);
+       task->simdata = simdata;
+
+       /* Task structure */
+       task->name = xbt_strdup(name);
+       task->data = data;
+
+       /* Simulator Data */
+       simdata->computation_amount = 0;
+       simdata->message_size = 0;
+       simdata->cond = SIMIX_cond_init();
+       simdata->mutex = SIMIX_mutex_init();
+       simdata->compute = NULL;
+       simdata->comm = NULL;
+       simdata->rate = -1.0;
+       simdata->refcount = 1;
+       simdata->sender = NULL;
+       simdata->receiver = NULL;
+       simdata->source = NULL;
+
+       simdata->host_nb = host_nb;
+       simdata->host_list = xbt_new0(smx_host_t, host_nb);
+       simdata->comp_amount = computation_amount;
+       simdata->comm_amount = communication_amount;
+
+       for (i = 0; i < host_nb; i++)
+               simdata->host_list[i] = host_list[i]->simdata->smx_host;
+
+       return task;
+}
+
+MSG_error_t MSG_parallel_task_execute(m_task_t task)
 {
-  return MSG_task_get_with_time_out(task, channel, -1);
+       simdata_task_t simdata = NULL;
+       m_process_t self = MSG_process_self();
+       e_surf_action_state_t state = SURF_ACTION_NOT_IN_THE_SYSTEM;
+       CHECK_HOST();
+
+       simdata = task->simdata;
+
+       xbt_assert0((!simdata->compute)
+                       && (task->simdata->refcount == 1),
+                       "This task is executed somewhere else. Go fix your code!");
+
+       xbt_assert0(simdata->host_nb, "This is not a parallel task. Go to hell.");
+
+       DEBUG1("Computing on %s", MSG_process_self()->simdata->m_host->name);
+
+       simdata->refcount++;
+
+       SIMIX_mutex_lock(simdata->mutex);
+       simdata->compute =
+               SIMIX_action_parallel_execute(task->name, simdata->host_nb,
+                               simdata->host_list, simdata->comp_amount,
+                               simdata->comm_amount, 1.0, -1.0);
+
+       self->simdata->waiting_action = simdata->compute;
+       SIMIX_register_action_to_condition(simdata->compute, simdata->cond);
+       do {
+               SIMIX_cond_wait(simdata->cond, simdata->mutex);
+               state = SIMIX_action_get_state(task->simdata->compute);
+       } while (state == SURF_ACTION_READY || state == SURF_ACTION_RUNNING);
+
+       SIMIX_unregister_action_to_condition(simdata->compute, simdata->cond);
+       self->simdata->waiting_action = NULL;
+
+
+       SIMIX_mutex_unlock(simdata->mutex);
+       simdata->refcount--;
+
+       if (SIMIX_action_get_state(task->simdata->compute) == SURF_ACTION_DONE) {
+               /* action ended, set comm and compute = NULL, the actions is already destroyed in the main function */
+               SIMIX_action_destroy(task->simdata->compute);
+               simdata->computation_amount = 0.0;
+               simdata->comm = NULL;
+               simdata->compute = NULL;
+               MSG_RETURN(MSG_OK);
+       } else if (SIMIX_host_get_state(SIMIX_host_self()) == 0) {
+               /* action ended, set comm and compute = NULL, the actions is already destroyed in the main function */
+               SIMIX_action_destroy(task->simdata->compute);
+               simdata->comm = NULL;
+               simdata->compute = NULL;
+               MSG_RETURN(MSG_HOST_FAILURE);
+       } else {
+               /* action ended, set comm and compute = NULL, the actions is already destroyed in the main function */
+               SIMIX_action_destroy(task->simdata->compute);
+               simdata->comm = NULL;
+               simdata->compute = NULL;
+               MSG_RETURN(MSG_TASK_CANCELLED);
+       }
+
 }
 
+
 /** \ingroup msg_gos_functions
- * \brief Listen on a channel and wait for receiving a task with a timeout.
+ * \brief Sleep for the specified number of seconds
  *
- * It takes three parameters.
- * \param task a memory location for storing a #m_task_t. It will
-   hold a task when this function will return. Thus \a task should not
-   be equal to \c NULL and \a *task should be equal to \c NULL. If one of
-   those two condition does not hold, there will be a warning message.
- * \param channel the channel on which the agent should be
-   listening. This value has to be >=0 and < than the maximal
-   number of channels fixed with MSG_set_channel_number().
- * \param max_duration the maximum time to wait for a task before giving
-    up. In such a case, \a task will not be modified and will still be
-    equal to \c NULL when returning.
- * \return #MSG_FATAL if \a task is equal to \c NULL, #MSG_WARNING
-   if \a *task is not equal to \c NULL, and #MSG_OK otherwise.
+ * Makes the current process sleep until \a time seconds have elapsed.
+ *
+ * \param nb_sec a number of second
  */
-MSG_error_t MSG_task_get_with_time_out(m_task_t * task,
-                                      m_channel_t channel,
-                                      double max_duration)
+MSG_error_t MSG_process_sleep(double nb_sec)
 {
-  return __MSG_task_get_with_time_out_from_host(task, channel, max_duration, NULL);
+       smx_action_t act_sleep;
+       m_process_t proc = MSG_process_self();
+       e_surf_action_state_t state = SURF_ACTION_NOT_IN_THE_SYSTEM;
+       smx_mutex_t mutex;
+       smx_cond_t cond;
+
+#ifdef HAVE_TRACING
+       TRACE_msg_process_sleep_in (MSG_process_self());
+#endif
+
+       /* create action to sleep */
+       act_sleep =
+               SIMIX_action_sleep(SIMIX_process_get_host(proc->simdata->s_process),
+                               nb_sec);
+
+       mutex = SIMIX_mutex_init();
+       SIMIX_mutex_lock(mutex);
+
+       /* create conditional and register action to it */
+       cond = SIMIX_cond_init();
+
+       proc->simdata->waiting_action = act_sleep;
+       SIMIX_register_action_to_condition(act_sleep, cond);
+       do {
+               SIMIX_cond_wait(cond, mutex);
+               state = SIMIX_action_get_state(act_sleep);
+       } while (state == SURF_ACTION_READY || state == SURF_ACTION_RUNNING);
+       proc->simdata->waiting_action = NULL;
+       SIMIX_unregister_action_to_condition(act_sleep, cond);
+       SIMIX_mutex_unlock(mutex);
+
+       /* remove variables */
+       SIMIX_cond_destroy(cond);
+       SIMIX_mutex_destroy(mutex);
+
+       if (SIMIX_action_get_state(act_sleep) == SURF_ACTION_DONE) {
+               if (SIMIX_host_get_state(SIMIX_host_self()) == SURF_RESOURCE_OFF) {
+                       SIMIX_action_destroy(act_sleep);
+#ifdef HAVE_TRACING
+                       TRACE_msg_process_sleep_out (MSG_process_self());
+#endif
+                       MSG_RETURN(MSG_HOST_FAILURE);
+               }
+       } else {
+               SIMIX_action_destroy(act_sleep);
+#ifdef HAVE_TRACING
+               TRACE_msg_process_sleep_out (MSG_process_self());
+#endif
+               MSG_RETURN(MSG_HOST_FAILURE);
+       }
+
+       SIMIX_action_destroy(act_sleep);
+#ifdef HAVE_TRACING
+       TRACE_msg_process_sleep_out (MSG_process_self());
+#endif
+       MSG_RETURN(MSG_OK);
 }
 
 /** \ingroup msg_gos_functions
@@ -184,180 +305,202 @@ MSG_error_t MSG_task_get_with_time_out(m_task_t * task,
  *
  * It takes three parameters.
  * \param task a memory location for storing a #m_task_t. It will
  hold a task when this function will return. Thus \a task should not
  be equal to \c NULL and \a *task should be equal to \c NULL. If one of
  those two condition does not hold, there will be a warning message.
+ hold a task when this function will return. Thus \a task should not
+ be equal to \c NULL and \a *task should be equal to \c NULL. If one of
+ those two condition does not hold, there will be a warning message.
  * \param channel the channel on which the agent should be
  listening. This value has to be >=0 and < than the maximal
  number of channels fixed with MSG_set_channel_number().
+ listening. This value has to be >=0 and < than the maximal
+ number of channels fixed with MSG_set_channel_number().
  * \param host the host that is to be watched.
  * \return #MSG_FATAL if \a task is equal to \c NULL, #MSG_WARNING
  if \a *task is not equal to \c NULL, and #MSG_OK otherwise.
+ if \a *task is not equal to \c NULL, and #MSG_OK otherwise.
  */
-MSG_error_t MSG_task_get_from_host(m_task_t * task, int channel, 
-                                  m_host_t host)
+       MSG_error_t
+MSG_task_get_from_host(m_task_t * task, m_channel_t channel, m_host_t host)
 {
-  return __MSG_task_get_with_time_out_from_host(task, channel, -1, host);
+       return MSG_task_get_ext(task, channel, -1, host);
 }
 
 /** \ingroup msg_gos_functions
- * \brief Test whether there is a pending communication on a channel.
+ * \brief Listen on a channel and wait for receiving a task.
  *
- * It takes one parameter.
+ * It takes two parameters.
+ * \param task a memory location for storing a #m_task_t. It will
+ hold a task when this function will return. Thus \a task should not
+ be equal to \c NULL and \a *task should be equal to \c NULL. If one of
+ those two condition does not hold, there will be a warning message.
  * \param channel the channel on which the agent should be
-   listening. This value has to be >=0 and < than the maximal
-   number of channels fixed with MSG_set_channel_number().
- * \return 1 if there is a pending communication and 0 otherwise
+ listening. This value has to be >=0 and < than the maximal
+ number of channels fixed with MSG_set_channel_number().
+ * \return #MSG_FATAL if \a task is equal to \c NULL, #MSG_WARNING
+ * if \a *task is not equal to \c NULL, and #MSG_OK otherwise.
  */
-int MSG_task_Iprobe(m_channel_t channel)
+MSG_error_t MSG_task_get(m_task_t * task, m_channel_t channel)
 {
-  m_host_t h = NULL;
-  simdata_host_t h_simdata = NULL;
-
-  xbt_assert1((channel>=0) && (channel < msg_global->max_channel),"Invalid channel %d",channel);
-  DEBUG2("Probing on channel %d (%s)", channel,h->name);
-  CHECK_HOST();
-  h = MSG_host_self();
-  h_simdata = h->simdata;
-  return(xbt_fifo_get_first_item(h_simdata->mbox[channel])!=NULL);
+       return MSG_task_get_with_timeout(task, channel, -1);
 }
 
 /** \ingroup msg_gos_functions
- * \brief Test whether there is a pending communication on a channel, and who sent it.
+ * \brief Listen on a channel and wait for receiving a task with a timeout.
  *
- * It takes one parameter.
+ * It takes three parameters.
+ * \param task a memory location for storing a #m_task_t. It will
+ hold a task when this function will return. Thus \a task should not
+ be equal to \c NULL and \a *task should be equal to \c NULL. If one of
+ those two condition does not hold, there will be a warning message.
  * \param channel the channel on which the agent should be
-   listening. This value has to be >=0 and < than the maximal
-   number of channels fixed with MSG_set_channel_number().
- * \return -1 if there is no pending communication and the PID of the process who sent it otherwise
+ listening. This value has to be >=0 and < than the maximal
+ number of channels fixed with MSG_set_channel_number().
+ * \param max_duration the maximum time to wait for a task before giving
+ up. In such a case, #MSG_TRANSFER_FAILURE will be returned, \a task
+ will not be modified and will still be
+ equal to \c NULL when returning.
+ * \return #MSG_FATAL if \a task is equal to \c NULL, #MSG_WARNING
+ if \a *task is not equal to \c NULL, and #MSG_OK otherwise.
  */
-int MSG_task_probe_from(m_channel_t channel)
+       MSG_error_t
+MSG_task_get_with_timeout(m_task_t * task, m_channel_t channel,
+               double max_duration)
 {
-  m_host_t h = NULL;
-  simdata_host_t h_simdata = NULL;
-  xbt_fifo_item_t item;
-  m_task_t t;
-
-  xbt_assert1((channel>=0) && (channel < msg_global->max_channel),"Invalid channel %d",channel);
-  CHECK_HOST();
-  h = MSG_host_self();
-  h_simdata = h->simdata;
-
-  DEBUG2("Probing on channel %d (%s)", channel,h->name);
-   
-  item = xbt_fifo_get_first_item(h->simdata->mbox[channel]);
-  if (!item || !(t = xbt_fifo_get_item_content(item)))
-    return -1;
-   
-  return MSG_process_get_PID(t->simdata->sender);
+       return MSG_task_get_ext(task, channel, max_duration, NULL);
 }
 
-/** \ingroup msg_gos_functions
- * \brief Wait for at most \a max_duration second for a task reception
-   on \a channel. *\a PID is updated with the PID of the first process
-   that triggered this event is any.
- *
- * It takes three parameters:
- * \param channel the channel on which the agent should be
-   listening. This value has to be >=0 and < than the maximal.
-   number of channels fixed with MSG_set_channel_number().
- * \param PID a memory location for storing an int.
- * \param max_duration the maximum time to wait for a task before
-    giving up. In the case of a reception, *\a PID will be updated
-    with the PID of the first process to send a task.
- * \return #MSG_HOST_FAILURE if the host is shut down in the meantime
-   and #MSG_OK otherwise.
+/** \defgroup msg_gos_functions MSG Operating System Functions
+ *  \brief This section describes the functions that can be used
+ *  by an agent for handling some task.
  */
-MSG_error_t MSG_channel_select_from(m_channel_t channel, double max_duration,
-                                   int *PID)
+
+       MSG_error_t
+MSG_task_get_ext(m_task_t * task, m_channel_t channel, double timeout,
+               m_host_t host)
 {
-  m_host_t h = NULL;
-  simdata_host_t h_simdata = NULL;
-  xbt_fifo_item_t item;
-  m_task_t t;
-  int first_time = 1;
-  m_process_t process = MSG_process_self();
-
-  xbt_assert1((channel>=0) && (channel < msg_global->max_channel),"Invalid channel %d",channel);
-  if(PID) {
-    *PID = -1;
-  }
-
-  if(max_duration==0.0) {
-    return MSG_task_probe_from(channel);
-  } else {
-    CHECK_HOST();
-    h = MSG_host_self();
-    h_simdata = h->simdata;
-    
-    DEBUG2("Probing on channel %d (%s)", channel,h->name);
-    while(!(item = xbt_fifo_get_first_item(h->simdata->mbox[channel]))) {
-      if(max_duration>0) {
-       if(!first_time) {
-         MSG_RETURN(MSG_OK);
-       }
-      }
-      xbt_assert2(!(h_simdata->sleeping[channel]),
-                 "A process (%s(%d)) is already blocked on this channel",
-                 h_simdata->sleeping[channel]->name,
-                 h_simdata->sleeping[channel]->simdata->PID);
-      h_simdata->sleeping[channel] = process; /* I'm waiting. Wake me up when you're ready */
-      if(max_duration>0) {
-       __MSG_process_block(max_duration);
-      } else {
-       __MSG_process_block(-1);
-      }
-      if(surf_workstation_resource->extension_public->get_state(h_simdata->host) 
-        == SURF_CPU_OFF) {
-       MSG_RETURN(MSG_HOST_FAILURE);
-      }
-      h_simdata->sleeping[channel] = NULL;
-      first_time = 0;
-    }
-    if (!item || !(t = xbt_fifo_get_item_content(item))) {
-      MSG_RETURN(MSG_OK);
-    }
-    if(PID) {
-      *PID = MSG_process_get_PID(t->simdata->sender);
-    }
-    MSG_RETURN(MSG_OK);
-  }
+       xbt_assert1((channel >= 0)
+                       && (channel < msg_global->max_channel), "Invalid channel %d",
+                       channel);
+
+       return
+               MSG_mailbox_get_task_ext(MSG_mailbox_get_by_channel
+                               (MSG_host_self(), channel), task, host, timeout);
 }
 
+       MSG_error_t
+MSG_task_receive_from_host(m_task_t * task, const char *alias, m_host_t host)
+{
+       return MSG_task_receive_ext(task, alias, -1, host);
+}
 
-/** \ingroup msg_gos_functions
+MSG_error_t MSG_task_receive(m_task_t * task, const char *alias)
+{
+       return MSG_task_receive_with_timeout(task, alias, -1);
+}
 
- * \brief Return the number of tasks waiting to be received on a \a
-   channel and sent by \a host.
- *
- * It takes two parameters.
- * \param channel the channel on which the agent should be
-   listening. This value has to be >=0 and < than the maximal
-   number of channels fixed with MSG_set_channel_number().
- * \param host the host that is to be watched.
- * \return the number of tasks waiting to be received on \a channel
-   and sent by \a host.
- */
-int MSG_task_probe_from_host(int channel, m_host_t host)
+       MSG_error_t
+MSG_task_receive_with_timeout(m_task_t * task, const char *alias,
+               double timeout)
 {
-  simdata_host_t h_simdata = NULL;
-  xbt_fifo_item_t item;
-  m_task_t t;
-  int count = 0;
-  m_host_t h = NULL;
-  
-  xbt_assert1((channel>=0) && (channel < msg_global->max_channel),"Invalid channel %d",channel);
-  CHECK_HOST();
-  h = MSG_host_self();
-  h_simdata = h->simdata;
-
-  DEBUG2("Probing on channel %d (%s)", channel,h->name);
-   
-  xbt_fifo_foreach(h->simdata->mbox[channel],item,t,m_task_t) {
-    if(t->simdata->source==host) count++;
-  }
-   
-  return count;
+       return MSG_task_receive_ext(task, alias, timeout, NULL);
+}
+
+       MSG_error_t
+MSG_task_receive_ext(m_task_t * task, const char *alias, double timeout,
+               m_host_t host)
+{
+       return MSG_mailbox_get_task_ext(MSG_mailbox_get_by_alias(alias), task, host,
+                       timeout);
+}
+
+msg_comm_t MSG_task_isend(m_task_t task, const char *alias) {
+       simdata_task_t t_simdata = NULL;
+       m_process_t process = MSG_process_self();
+       msg_mailbox_t mailbox = MSG_mailbox_get_by_alias(alias);
+
+       CHECK_HOST();
+
+       /* FIXME: these functions are not tracable */
+
+       /* Prepare the task to send */
+       t_simdata = task->simdata;
+       t_simdata->sender = process;
+       t_simdata->source = MSG_host_self();
+
+       xbt_assert0(t_simdata->refcount == 1,
+                       "This task is still being used somewhere else. You cannot send it now. Go fix your code!");
+
+       t_simdata->refcount++;
+       msg_global->sent_msg++;
+       process->simdata->waiting_task = task;
+
+       /* Send it by calling SIMIX network layer */
+
+       /* Kept for semantical compatibility with older implementation */
+       if(mailbox->cond)
+               SIMIX_cond_signal(mailbox->cond);
+
+       return SIMIX_network_isend(mailbox->rdv, t_simdata->message_size, t_simdata->rate,
+                       task, sizeof(void*), &t_simdata->comm);
+}
+
+msg_comm_t MSG_task_irecv(m_task_t * task, const char *alias) {
+       smx_comm_t comm;
+       smx_rdv_t rdv = MSG_mailbox_get_by_alias(alias)->rdv;
+       msg_mailbox_t mailbox=MSG_mailbox_get_by_alias(alias);
+       size_t size = sizeof(void*);
+
+       CHECK_HOST();
+
+       /* FIXME: these functions are not tracable */
+
+       memset(&comm,0,sizeof(comm));
+
+       /* Kept for compatibility with older implementation */
+       xbt_assert1(!MSG_mailbox_get_cond(mailbox),
+                       "A process is already blocked on this channel %s",
+                       MSG_mailbox_get_alias(mailbox));
+
+       /* Sanity check */
+       xbt_assert0(task, "Null pointer for the task storage");
+
+       if (*task)
+               CRITICAL0("MSG_task_get() was asked to write in a non empty task struct.");
+
+       /* Try to receive it by calling SIMIX network layer */
+       return SIMIX_network_irecv(rdv, task, &size);
+}
+int MSG_comm_test(msg_comm_t comm) {
+       return SIMIX_network_test(comm);
+}
+
+MSG_error_t MSG_comm_wait(msg_comm_t comm, double timeout) {
+       xbt_ex_t e;
+       MSG_error_t res = MSG_OK;
+       TRY {
+               SIMIX_network_wait(comm,timeout);
+
+               if(!(comm->src_proc == SIMIX_process_self()))
+               {
+                       m_task_t  task;
+                       task = (m_task_t) SIMIX_communication_get_src_buf(comm);
+                       task->simdata->refcount--;
+               }
+
+               /* FIXME: these functions are not tracable */
+       }  CATCH(e){
+               switch(e.category){
+                       case host_error:
+                               res = MSG_HOST_FAILURE;
+                               break;
+                       case network_error:
+                               res = MSG_TRANSFER_FAILURE;
+                               break;
+                       case timeout_error:
+                               res = MSG_TIMEOUT;
+                               break;
+                       default:
+                               xbt_die(bprintf("Unhandled SIMIX network exception: %s",e.msg));
+               }
+               xbt_ex_free(e);
+       }
+       return res;
 }
 
 /** \ingroup msg_gos_functions
@@ -367,359 +510,370 @@ int MSG_task_probe_from_host(int channel, m_host_t host)
  * This function is used for describing the behavior of an agent. It
  * takes three parameter.
  * \param task a #m_task_t to send on another location. This task
  will not be usable anymore when the function will return. There is
  no automatic task duplication and you have to save your parameters
  before calling this function. Tasks are unique and once it has been
  sent to another location, you should not access it anymore. You do
  not need to call MSG_task_destroy() but to avoid using, as an
  effect of inattention, this task anymore, you definitely should
  renitialize it with #MSG_TASK_UNINITIALIZED. Note that this task
  can be transfered iff it has been correctly created with
  MSG_task_create().
+ will not be usable anymore when the function will return. There is
+ no automatic task duplication and you have to save your parameters
+ before calling this function. Tasks are unique and once it has been
+ sent to another location, you should not access it anymore. You do
+ not need to call MSG_task_destroy() but to avoid using, as an
+ effect of inattention, this task anymore, you definitely should
+ renitialize it with #MSG_TASK_UNINITIALIZED. Note that this task
+ can be transfered iff it has been correctly created with
+ MSG_task_create().
  * \param dest the destination of the message
  * \param channel the channel on which the agent should put this
  task. This value has to be >=0 and < than the maximal number of
  channels fixed with MSG_set_channel_number().
+ task. This value has to be >=0 and < than the maximal number of
+ channels fixed with MSG_set_channel_number().
  * \return #MSG_FATAL if \a task is not properly initialized and
- * #MSG_OK otherwise.
+ * #MSG_OK otherwise. Returns #MSG_HOST_FAILURE if the host on which
+ * this function was called was shut down. Returns
+ * #MSG_TRANSFER_FAILURE if the transfer could not be properly done
+ * (network failure, dest failure)
  */
-MSG_error_t MSG_task_put(m_task_t task,
-                        m_host_t dest, m_channel_t channel)
+MSG_error_t MSG_task_put(m_task_t task, m_host_t dest, m_channel_t channel)
 {
-  m_process_t process = MSG_process_self();
-  simdata_task_t task_simdata = NULL;
-  e_surf_action_state_t state = SURF_ACTION_NOT_IN_THE_SYSTEM;
-  m_host_t local_host = NULL;
-  m_host_t remote_host = NULL;
-
-  CHECK_HOST();
-
-  xbt_assert1((channel>=0) && (channel < msg_global->max_channel),"Invalid channel %d",channel);
-
-  task_simdata = task->simdata;
-  task_simdata->sender = process;
-  task_simdata->source = MSG_process_get_host(process);
-  xbt_assert0(task_simdata->using==1,"Gargl!");
-  task_simdata->comm = NULL;
-  
-  local_host = ((simdata_process_t) process->simdata)->host;
-  remote_host = dest;
-
-  DEBUG4("Trying to send a task (%g Mb) from %s to %s on channel %d", 
-        task->simdata->message_size,local_host->name, remote_host->name, channel);
-
-  xbt_fifo_push(((simdata_host_t) remote_host->simdata)->
-               mbox[channel], task);
-
-  PAJE_COMM_START(process,task,channel);
-    
-  if(remote_host->simdata->sleeping[channel]) {
-    DEBUG0("Somebody is listening. Let's wake him up!");
-    __MSG_process_unblock(remote_host->simdata->sleeping[channel]);
-  }
-
-  process->simdata->put_host = dest;
-  process->simdata->put_channel = channel;
-  while(!(task_simdata->comm)) {
-    DEBUG0("Communication not initiated yet. Let's block!");
-    __MSG_process_block(-1);
-  }
-  DEBUG0("Registering to this communication");
-  surf_workstation_resource->common_public->action_use(task_simdata->comm);
-  process->simdata->put_host = NULL;
-  process->simdata->put_channel = -1;
-
-
-  PAJE_PROCESS_PUSH_STATE(process,"C");  
-
-  state=surf_workstation_resource->common_public->action_get_state(task_simdata->comm);
-  while (state==SURF_ACTION_RUNNING) {
-    DEBUG0("Waiting for action termination");
-    __MSG_task_wait_event(process, task);
-    state=surf_workstation_resource->common_public->action_get_state(task_simdata->comm);
-  }
-  DEBUG0("Action terminated");
-
-  PAJE_PROCESS_POP_STATE(process);  
-
-  if(state == SURF_ACTION_DONE) {
-    if(surf_workstation_resource->common_public->action_free(task_simdata->comm)) 
-      task_simdata->comm = NULL;
-    MSG_task_destroy(task);
-    MSG_RETURN(MSG_OK);
-  } else if(surf_workstation_resource->extension_public->get_state(local_host->simdata->host) 
-           == SURF_CPU_OFF) {
-    if(surf_workstation_resource->common_public->action_free(task_simdata->comm)) 
-      task_simdata->comm = NULL;
-    MSG_task_destroy(task);
-    MSG_RETURN(MSG_HOST_FAILURE);
-  } else { 
-    if(surf_workstation_resource->common_public->action_free(task_simdata->comm)) 
-      task_simdata->comm = NULL;
-    MSG_task_destroy(task);
-    MSG_RETURN(MSG_TRANSFER_FAILURE);
-  }
+       return MSG_task_put_with_timeout(task, dest, channel, -1.0);
 }
 
 /** \ingroup msg_gos_functions
- * \brief Does exactly the same as MSG_task_put but with a bounded transmition 
+ * \brief Does exactly the same as MSG_task_put but with a bounded transmition
  * rate.
  *
  * \sa MSG_task_put
  */
-MSG_error_t MSG_task_put_bounded(m_task_t task,
-                                m_host_t dest, m_channel_t channel,
-                                double max_rate)
+       MSG_error_t
+MSG_task_put_bounded(m_task_t task, m_host_t dest, m_channel_t channel,
+               double maxrate)
 {
-  MSG_error_t res = MSG_OK;
-  task->simdata->rate=max_rate;
-  res = MSG_task_put(task, dest, channel);
-  task->simdata->rate=-1.0;
-  return(res);
+       task->simdata->rate = maxrate;
+       return MSG_task_put(task, dest, channel);
 }
 
-/** \ingroup msg_gos_functions
- * \brief Executes a task and waits for its termination.
+/** \ingroup msg_gos_functions \brief Put a task on a channel of an
+ * host (with a timeout on the waiting of the destination host) and
+ * waits for the end of the transmission.
  *
  * This function is used for describing the behavior of an agent. It
- * takes only one parameter.
- * \param task a #m_task_t to execute on the location on which the
-   agent is running.
+ * takes four parameter.
+ * \param task a #m_task_t to send on another location. This task
+ will not be usable anymore when the function will return. There is
+ no automatic task duplication and you have to save your parameters
+ before calling this function. Tasks are unique and once it has been
+ sent to another location, you should not access it anymore. You do
+ not need to call MSG_task_destroy() but to avoid using, as an
+ effect of inattention, this task anymore, you definitely should
+ renitialize it with #MSG_TASK_UNINITIALIZED. Note that this task
+ can be transfered iff it has been correctly created with
+ MSG_task_create().
+ * \param dest the destination of the message
+ * \param channel the channel on which the agent should put this
+ task. This value has to be >=0 and < than the maximal number of
+ channels fixed with MSG_set_channel_number().
+ * \param timeout the maximum time to wait for a task before giving
+ up. In such a case, #MSG_TRANSFER_FAILURE will be returned, \a task
+ will not be modified
  * \return #MSG_FATAL if \a task is not properly initialized and
- * #MSG_OK otherwise.
+#MSG_OK otherwise. Returns #MSG_HOST_FAILURE if the host on which
+this function was called was shut down. Returns
+#MSG_TRANSFER_FAILURE if the transfer could not be properly done
+(network failure, dest failure, timeout...)
  */
-MSG_error_t MSG_task_execute(m_task_t task)
+       MSG_error_t
+MSG_task_put_with_timeout(m_task_t task, m_host_t dest, m_channel_t channel,
+               double timeout)
 {
-  m_process_t process = MSG_process_self();
-  MSG_error_t res;
+       xbt_assert1((channel >= 0)
+                       && (channel < msg_global->max_channel), "Invalid channel %d",
+                       channel);
 
-  DEBUG1("Computing on %s", process->simdata->host->name);
-
-  __MSG_task_execute(process, task);
-
-  PAJE_PROCESS_PUSH_STATE(process,"E");  
-  res = __MSG_wait_for_computation(process,task);
-  PAJE_PROCESS_POP_STATE(process);
-  return res;
+       return
+               MSG_mailbox_put_with_timeout(MSG_mailbox_get_by_channel(dest, channel),
+                               task, timeout);
 }
 
-void __MSG_task_execute(m_process_t process, m_task_t task)
+MSG_error_t MSG_task_send(m_task_t task, const char *alias)
 {
-  simdata_task_t simdata = NULL;
+       return MSG_task_send_with_timeout(task, alias, -1);
+}
 
-  CHECK_HOST();
 
-  simdata = task->simdata;
+       MSG_error_t
+MSG_task_send_bounded(m_task_t task, const char *alias, double maxrate)
+{
+       task->simdata->rate = maxrate;
+       return MSG_task_send(task, alias);
+}
 
-  simdata->compute = surf_workstation_resource->extension_public->
-    execute(MSG_process_get_host(process)->simdata->host,
-           simdata->computation_amount);
-  surf_workstation_resource->common_public->
-    set_priority(simdata->compute, simdata->priority);
 
-  surf_workstation_resource->common_public->action_set_data(simdata->compute,task);
+       MSG_error_t
+MSG_task_send_with_timeout(m_task_t task, const char *alias, double timeout)
+{
+       return MSG_mailbox_put_with_timeout(MSG_mailbox_get_by_alias(alias), task,
+                       timeout);
 }
 
-MSG_error_t __MSG_wait_for_computation(m_process_t process, m_task_t task)
+int MSG_task_listen(const char *alias)
 {
-  e_surf_action_state_t state = SURF_ACTION_NOT_IN_THE_SYSTEM;
-  simdata_task_t simdata = task->simdata;
-
-  simdata->using++;
-  do {
-    __MSG_task_wait_event(process, task);
-    state=surf_workstation_resource->common_public->action_get_state(simdata->compute);
-  } while (state==SURF_ACTION_RUNNING);
-  simdata->using--;
-    
-
-  if(state == SURF_ACTION_DONE) {
-    if(surf_workstation_resource->common_public->action_free(simdata->compute)) 
-      simdata->compute = NULL;
-    simdata->computation_amount = 0.0;
-    MSG_RETURN(MSG_OK);
-  } else if(surf_workstation_resource->extension_public->
-           get_state(MSG_process_get_host(process)->simdata->host) 
-           == SURF_CPU_OFF) {
-    if(surf_workstation_resource->common_public->action_free(simdata->compute)) 
-      simdata->compute = NULL;
-    MSG_RETURN(MSG_HOST_FAILURE);
-  } else {
-    if(surf_workstation_resource->common_public->action_free(simdata->compute)) 
-      simdata->compute = NULL;
-    MSG_RETURN(MSG_TASK_CANCELLED);
-  }
+       CHECK_HOST();
+
+       return !MSG_mailbox_is_empty(MSG_mailbox_get_by_alias(alias));
 }
-/** \ingroup m_task_management
- * \brief Creates a new #m_task_t (a parallel one....).
+
+/** \ingroup msg_gos_functions
+ * \brief Test whether there is a pending communication on a channel.
  *
- * A constructor for #m_task_t taking six arguments and returning the 
-   corresponding object.
- * \param name a name for the object. It is for user-level information
-   and can be NULL.
- * \param host_nb the number of hosts implied in the parallel task.
- * \param host_list an array of \p host_nb m_host_t.
- * \param computation_amount an array of \p host_nb
-   doubles. computation_amount[i] is the total number of operations
-   that have to be performed on host_list[i].
- * \param communication_amount an array of \p host_nb* \p host_nb doubles.
- * \param data a pointer to any data may want to attach to the new
-   object.  It is for user-level information and can be NULL. It can
-   be retrieved with the function \ref MSG_task_get_data.
- * \see m_task_t
- * \return The new corresponding object.
+ * It takes one parameter.
+ * \param channel the channel on which the agent should be
+ listening. This value has to be >=0 and < than the maximal
+ number of channels fixed with MSG_set_channel_number().
+ * \return 1 if there is a pending communication and 0 otherwise
  */
-m_task_t MSG_parallel_task_create(const char *name, 
-                                 int host_nb,
-                                 const m_host_t *host_list,
-                                 double *computation_amount,
-                                 double *communication_amount,
-                                 void *data)
+int MSG_task_Iprobe(m_channel_t channel)
 {
-  simdata_task_t simdata = xbt_new0(s_simdata_task_t,1);
-  m_task_t task = xbt_new0(s_m_task_t,1);
-  int i;
-
-  /* Task structure */
-  task->name = xbt_strdup(name);
-  task->simdata = simdata;
-  task->data = data;
-
-  /* Simulator Data */
-  simdata->sleeping = xbt_dynar_new(sizeof(m_process_t),NULL);
-  simdata->rate = -1.0;
-  simdata->using = 1;
-  simdata->sender = NULL;
-  simdata->source = NULL;
-  simdata->host_nb = host_nb;
-  
-  simdata->host_list = xbt_new0(void *, host_nb);
-  simdata->comp_amount = computation_amount;
-  simdata->comm_amount = communication_amount;
-
-  for(i=0;i<host_nb;i++)
-    simdata->host_list[i] = host_list[i]->simdata->host;
-
-  return task;
+       xbt_assert1((channel >= 0)
+                       && (channel < msg_global->max_channel), "Invalid channel %d",
+                       channel);
+
+       CHECK_HOST();
+
+       return
+               !MSG_mailbox_is_empty(MSG_mailbox_get_by_channel
+                               (MSG_host_self(), channel));
 }
 
+/** \ingroup msg_gos_functions
 
-static void __MSG_parallel_task_execute(m_process_t process, m_task_t task)
+ * \brief Return the number of tasks waiting to be received on a \a
+ channel and sent by \a host.
+ *
+ * It takes two parameters.
+ * \param channel the channel on which the agent should be
+ listening. This value has to be >=0 and < than the maximal
+ number of channels fixed with MSG_set_channel_number().
+ * \param host the host that is to be watched.
+ * \return the number of tasks waiting to be received on \a channel
+ and sent by \a host.
+ */
+int MSG_task_probe_from_host(int channel, m_host_t host)
 {
-  simdata_task_t simdata = NULL;
-
-  CHECK_HOST();
+       xbt_assert1((channel >= 0)
+                       && (channel < msg_global->max_channel), "Invalid channel %d",
+                       channel);
 
-  simdata = task->simdata;
+       CHECK_HOST();
 
-  xbt_assert0(simdata->host_nb,"This is not a parallel task. Go to hell.");
+       return
+               MSG_mailbox_get_count_host_waiting_tasks(MSG_mailbox_get_by_channel
+                               (MSG_host_self(), channel),
+                               host);
 
-  simdata->compute = surf_workstation_resource->extension_public->
-  execute_parallel_task(task->simdata->host_nb,
-                       task->simdata->host_list,
-                       task->simdata->comp_amount,
-                       task->simdata->comm_amount,
-                       1.0,
-                       -1.0);
-  if(simdata->compute)
-    surf_workstation_resource->common_public->action_set_data(simdata->compute,task);
 }
 
-MSG_error_t MSG_parallel_task_execute(m_task_t task)
+int MSG_task_listen_from_host(const char *alias, m_host_t host)
 {
-  m_process_t process = MSG_process_self();
-  MSG_error_t res;
-
-  DEBUG0("Computing on a tons of guys");
-  
-  __MSG_parallel_task_execute(process, task);
+       CHECK_HOST();
 
-  if(task->simdata->compute)
-    res = __MSG_wait_for_computation(process,task);
-  else 
-    res = MSG_OK;
-
-  return res;  
+       return
+               MSG_mailbox_get_count_host_waiting_tasks(MSG_mailbox_get_by_alias(alias),
+                               host);
 }
 
-
 /** \ingroup msg_gos_functions
- * \brief Sleep for the specified number of seconds
- *
- * Makes the current process sleep until \a time seconds have elapsed.
+ * \brief Test whether there is a pending communication on a channel, and who sent it.
  *
- * \param nb_sec a number of second
+ * It takes one parameter.
+ * \param channel the channel on which the agent should be
+ listening. This value has to be >=0 and < than the maximal
+ number of channels fixed with MSG_set_channel_number().
+ * \return -1 if there is no pending communication and the PID of the process who sent it otherwise
  */
-MSG_error_t MSG_process_sleep(double nb_sec)
+int MSG_task_probe_from(m_channel_t channel)
 {
-  e_surf_action_state_t state = SURF_ACTION_NOT_IN_THE_SYSTEM;
-  m_process_t process = MSG_process_self();
-  m_task_t dummy = NULL;
-  simdata_task_t simdata = NULL;
-
-  CHECK_HOST();
-  dummy = MSG_task_create("MSG_sleep", nb_sec, 0.0, NULL);
-  simdata = dummy->simdata;
-
-  simdata->compute = surf_workstation_resource->extension_public->
-    sleep(MSG_process_get_host(process)->simdata->host,
-           simdata->computation_amount);
-  surf_workstation_resource->common_public->action_set_data(simdata->compute,dummy);
-
-  
-  simdata->using++;
-  do {
-    __MSG_task_wait_event(process, dummy);
-    state=surf_workstation_resource->common_public->action_get_state(simdata->compute);
-  } while (state==SURF_ACTION_RUNNING);
-  simdata->using--;
-    
-  if(state == SURF_ACTION_DONE) {
-    if(surf_workstation_resource->extension_public->
-       get_state(MSG_process_get_host(process)->simdata->host) 
-       == SURF_CPU_OFF) {
-      if(surf_workstation_resource->common_public->action_free(simdata->compute)) 
-       simdata->compute = NULL;
-      MSG_RETURN(MSG_HOST_FAILURE);
-    }
-    if(__MSG_process_isBlocked(process)) {
-      __MSG_process_unblock(MSG_process_self());
-    }
-    if(surf_workstation_resource->extension_public->
-       get_state(MSG_process_get_host(process)->simdata->host) 
-       == SURF_CPU_OFF) {
-      if(surf_workstation_resource->common_public->action_free(simdata->compute)) 
-       simdata->compute = NULL;
-      MSG_RETURN(MSG_HOST_FAILURE);
-    }
-    if(surf_workstation_resource->common_public->action_free(simdata->compute)) 
-      simdata->compute = NULL;
-    MSG_task_destroy(dummy);
-    MSG_RETURN(MSG_OK);
-  } else MSG_RETURN(MSG_HOST_FAILURE);
+       m_task_t task;
+
+       CHECK_HOST();
+
+       xbt_assert1((channel >= 0)
+                       && (channel < msg_global->max_channel), "Invalid channel %d",
+                       channel);
+
+       if (NULL ==
+                       (task =
+                        MSG_mailbox_get_head(MSG_mailbox_get_by_channel
+                                (MSG_host_self(), channel))))
+               return -1;
+
+       return MSG_process_get_PID(task->simdata->sender);
 }
 
-/** \ingroup msg_gos_functions
- * \brief Return the number of MSG tasks currently running on a
- * the host of the current running process.
- */
-static int MSG_get_msgload(void) 
+int MSG_task_listen_from(const char *alias)
 {
-  m_process_t process;
-   
-  CHECK_HOST();
-  
-  xbt_assert0(0, "This function is still to be specified correctly (what do you mean by 'load', exactly?). In the meantime, please don't use it");
-  process = MSG_process_self();
-  return xbt_fifo_size(process->simdata->host->simdata->process_list);
+       m_task_t task;
+
+       CHECK_HOST();
+
+       if (NULL == (task = MSG_mailbox_get_head(MSG_mailbox_get_by_alias(alias))))
+               return -1;
+
+       return MSG_process_get_PID(task->simdata->sender);
 }
 
 /** \ingroup msg_gos_functions
+ * \brief Wait for at most \a max_duration second for a task reception
+ on \a channel.
+
+ * \a PID is updated with the PID of the first process that triggered this event if any.
  *
- * \brief Return the the last value returned by a MSG function (except
- * MSG_get_errno...).
+ * It takes three parameters:
+ * \param channel the channel on which the agent should be
+ listening. This value has to be >=0 and < than the maximal.
+ number of channels fixed with MSG_set_channel_number().
+ * \param PID a memory location for storing an int.
+ * \param timeout the maximum time to wait for a task before
+ giving up. In the case of a reception, *\a PID will be updated
+ with the PID of the first process to send a task.
+ * \return #MSG_HOST_FAILURE if the host is shut down in the meantime
+ and #MSG_OK otherwise.
  */
-MSG_error_t MSG_get_errno(void)
+       MSG_error_t
+MSG_channel_select_from(m_channel_t channel, double timeout, int *PID)
+{
+       m_host_t h = NULL;
+       simdata_host_t h_simdata = NULL;
+       m_task_t t;
+       int first_time = 1;
+       smx_cond_t cond;
+       msg_mailbox_t mailbox;
+
+       xbt_assert1((channel >= 0)
+                       && (channel < msg_global->max_channel), "Invalid channel %d",
+                       channel);
+
+       if (PID) {
+               *PID = -1;
+       }
+
+       if (timeout == 0.0) {
+               *PID = MSG_task_probe_from(channel);
+               MSG_RETURN(MSG_OK);
+       } else {
+               CHECK_HOST();
+               h = MSG_host_self();
+               h_simdata = h->simdata;
+
+               mailbox = MSG_mailbox_get_by_channel(MSG_host_self(), channel);
+
+               while (MSG_mailbox_is_empty(mailbox)) {
+                       if (timeout > 0) {
+                               if (!first_time) {
+                                       MSG_RETURN(MSG_OK);
+                               }
+                       }
+
+                       SIMIX_mutex_lock(h_simdata->mutex);
+
+                       xbt_assert1(!MSG_mailbox_get_cond(mailbox),
+                                       "A process is already blocked on this channel %d", channel);
+
+                       cond = SIMIX_cond_init();
+
+                       MSG_mailbox_set_cond(mailbox, cond);
+
+                       if (timeout > 0) {
+                               SIMIX_cond_wait_timeout(cond, h_simdata->mutex, timeout);
+                       } else {
+                               SIMIX_cond_wait(cond, h_simdata->mutex);
+                       }
+
+                       SIMIX_cond_destroy(cond);
+                       SIMIX_mutex_unlock(h_simdata->mutex);
+
+                       if (SIMIX_host_get_state(h_simdata->smx_host) == 0) {
+                               MSG_RETURN(MSG_HOST_FAILURE);
+                       }
+
+                       MSG_mailbox_set_cond(mailbox, NULL);
+                       first_time = 0;
+               }
+
+               if (NULL == (t = MSG_mailbox_get_head(mailbox)))
+                       MSG_RETURN(MSG_OK);
+
+
+               if (PID) {
+                       *PID = MSG_process_get_PID(t->simdata->sender);
+               }
+
+               MSG_RETURN(MSG_OK);
+       }
+}
+
+
+MSG_error_t MSG_alias_select_from(const char *alias, double timeout, int *PID)
 {
-  return PROCESS_GET_ERRNO();
+       m_host_t h = NULL;
+       simdata_host_t h_simdata = NULL;
+       m_task_t t;
+       int first_time = 1;
+       smx_cond_t cond;
+       msg_mailbox_t mailbox;
+
+       if (PID) {
+               *PID = -1;
+       }
+
+       if (timeout == 0.0) {
+               *PID = MSG_task_listen_from(alias);
+               MSG_RETURN(MSG_OK);
+       } else {
+               CHECK_HOST();
+               h = MSG_host_self();
+               h_simdata = h->simdata;
+
+               DEBUG2("Probing on alias %s (%s)", alias, h->name);
+
+               mailbox = MSG_mailbox_get_by_alias(alias);
+
+               while (MSG_mailbox_is_empty(mailbox)) {
+                       if (timeout > 0) {
+                               if (!first_time) {
+                                       MSG_RETURN(MSG_OK);
+                               }
+                       }
+
+                       SIMIX_mutex_lock(h_simdata->mutex);
+
+                       xbt_assert1(!MSG_mailbox_get_cond(mailbox),
+                                       "A process is already blocked on this alias %s", alias);
+
+                       cond = SIMIX_cond_init();
+
+                       MSG_mailbox_set_cond(mailbox, cond);
+
+                       if (timeout > 0) {
+                               SIMIX_cond_wait_timeout(cond, h_simdata->mutex, timeout);
+                       } else {
+                               SIMIX_cond_wait(cond, h_simdata->mutex);
+                       }
+
+                       SIMIX_cond_destroy(cond);
+                       SIMIX_mutex_unlock(h_simdata->mutex);
+
+                       if (SIMIX_host_get_state(h_simdata->smx_host) == 0) {
+                               MSG_RETURN(MSG_HOST_FAILURE);
+                       }
+
+                       MSG_mailbox_set_cond(mailbox, NULL);
+                       first_time = 0;
+               }
+
+               if (NULL == (t = MSG_mailbox_get_head(mailbox)))
+                       MSG_RETURN(MSG_OK);
+
+
+               if (PID) {
+                       *PID = MSG_process_get_PID(t->simdata->sender);
+               }
+
+               MSG_RETURN(MSG_OK);
+       }
 }