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cosmetics
[simgrid.git] / src / msg / gos.c
index 9ae49b2..bab9528 100644 (file)
@@ -5,10 +5,10 @@
 /* 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"xbt/sysdep.h"
-#include "xbt/error.h"
-XBT_LOG_NEW_DEFAULT_SUBCATEGORY(gos, msg,
+#include "private.h"
+#include "xbt/sysdep.h"
+#include "xbt/log.h"
+XBT_LOG_NEW_DEFAULT_SUBCATEGORY(msg_gos, msg,
                                "Logging specific to MSG (gos)");
 
 /** \defgroup msg_gos_functions MSG Operating System Functions
@@ -16,42 +16,23 @@ XBT_LOG_NEW_DEFAULT_SUBCATEGORY(gos, msg,
  *  by an agent for handling some task.
  */
 
-/** \ingroup msg_gos_functions
- * \brief This function is now deprecated and useless. Please stop using it.
- */
-MSG_error_t MSG_process_start(m_process_t process)
-{
-  xbt_assert0(0,"This function is now deprecated and useless. Please stop using it.");
-  
-  return MSG_OK;
-}
-
-/** \ingroup msg_gos_functions
- * \brief Listen on a channel and wait for receiving a task.
- *
- * It takes two parameter.
- * \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.
- */
-MSG_error_t MSG_task_get(m_task_t * task,
-                        m_channel_t channel)
+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)
 {
   m_process_t process = MSG_process_self();
   m_task_t t = NULL;
   m_host_t h = NULL;
+  m_task_t task_to_wait_for;
   simdata_task_t t_simdata = NULL;
   simdata_host_t h_simdata = NULL;
-  int warning = 0;
+  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");
 
@@ -64,20 +45,49 @@ MSG_error_t MSG_task_get(m_task_t * task,
 
   DEBUG2("Waiting for a task on channel %d (%s)", channel,h->name);
 
-  while ((t = xbt_fifo_pop(h_simdata->mbox[channel])) == NULL) {
-    xbt_assert2(!(h_simdata->sleeping[channel]),
-               "A process (%s(%d)) is already blocked on this channel",
+  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;
+       }
+       if(item) {
+         xbt_fifo_remove_item(h->simdata->mbox[channel],item);
+         break;
+       } 
+      }
+    }
+                                                      
+    if(max_duration>0) {
+      if(!first_time) {
+       PAJE_PROCESS_POP_STATE(process);
+       MSG_RETURN(MSG_TRANSFER_FAILURE);
+      }
+    }
+    xbt_assert3(!(h_simdata->sleeping[channel]),
+               "A process (%s(%d)) is already blocked on channel %d",
                h_simdata->sleeping[channel]->name,
-               h_simdata->sleeping[channel]->simdata->PID);
+               h_simdata->sleeping[channel]->simdata->PID,
+               channel);
     h_simdata->sleeping[channel] = process; /* I'm waiting. Wake me up when you're ready */
-    __MSG_process_block();
+    if(max_duration>0) {
+      __MSG_process_block(max_duration,"");
+    } else {
+      __MSG_process_block(-1,"");
+    }
+    h_simdata->sleeping[channel] = NULL;
+    first_time = 0;
     if(surf_workstation_resource->extension_public->get_state(h_simdata->host) 
        == SURF_CPU_OFF)
       MSG_RETURN(MSG_HOST_FAILURE);
-    h_simdata->sleeping[channel] = NULL;
     /* 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;
@@ -85,35 +95,135 @@ MSG_error_t MSG_task_get(m_task_t * task,
   /* Transfer */
   t_simdata->using++;
 
+  while(MSG_process_is_suspended(t_simdata->sender)) {
+    DEBUG1("Oooups, the sender (%s) has been suspended in the meantime. Let's wait for him", 
+          t_simdata->sender->name);
+    task_to_wait_for = t_simdata->sender->simdata->waiting_task;
+    if(__MSG_process_isBlocked(t_simdata->sender)) {
+      DEBUG0("He's blocked. Let's wait for him to go in the suspended state");
+      __MSG_process_unblock(t_simdata->sender);
+      task_to_wait_for->simdata->using++;
+      __MSG_task_wait_event(process, task_to_wait_for);
+      MSG_task_destroy(task_to_wait_for);
+    } else {
+      DEBUG0("He's suspended. Let's wait for him to go in the resumed state");
+      task_to_wait_for->simdata->using++;
+      __MSG_task_wait_event(process, task_to_wait_for);
+      MSG_task_destroy(task_to_wait_for);
+      DEBUG0("He's resumed. He should block again. So let's free him.");
+      __MSG_process_unblock(t_simdata->sender);
+      break;
+    }
+  }
+  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)) 
+  if(__MSG_process_isBlocked(t_simdata->sender)) {
+    DEBUG1("Unblocking %s",t_simdata->sender->name);
     __MSG_process_unblock(t_simdata->sender);
+  }
 
-  PAJE_PROCESS_PUSH_STATE(process,"C");  
+  PAJE_PROCESS_PUSH_STATE(process,"C",t);  
 
   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_PROCESS_POP_STATE(process);
   PAJE_COMM_STOP(process,t,channel);
 
-  if(state == SURF_ACTION_DONE) MSG_RETURN(MSG_OK);
-  else if(surf_workstation_resource->extension_public->get_state(h_simdata->host) 
-         == SURF_CPU_OFF)
+  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 MSG_RETURN(MSG_TRANSFER_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.
+ *
+ * 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.
+ */
+MSG_error_t MSG_task_get(m_task_t * task,
+                        m_channel_t channel)
+{
+  return MSG_task_get_with_time_out(task, channel, -1);
+}
+
+/** \ingroup msg_gos_functions
+ * \brief Listen on a channel and wait for receiving a task with a timeout.
+ *
+ * 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, #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.
+ */
+MSG_error_t MSG_task_get_with_time_out(m_task_t * task,
+                                      m_channel_t channel,
+                                      double max_duration)
+{
+  return __MSG_task_get_with_time_out_from_host(task, channel, max_duration, NULL);
+}
+
+/** \ingroup msg_gos_functions
+ * \brief Listen on \a channel and waits for receiving a task from \a host.
+ *
+ * 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 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.
+ */
+MSG_error_t MSG_task_get_from_host(m_task_t * task, int channel, 
+                                  m_host_t host)
+{
+  return __MSG_task_get_with_time_out_from_host(task, channel, -1, host);
 }
 
 /** \ingroup msg_gos_functions
@@ -128,13 +238,12 @@ MSG_error_t MSG_task_get(m_task_t * task,
 int MSG_task_Iprobe(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_getFirstItem(h_simdata->mbox[channel])!=NULL);
+  return(xbt_fifo_get_first_item(h->simdata->mbox[channel])!=NULL);
 }
 
 /** \ingroup msg_gos_functions
@@ -149,17 +258,16 @@ int MSG_task_Iprobe(m_channel_t channel)
 int MSG_task_probe_from(m_channel_t channel)
 {
   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_getFirstItem(h->simdata->mbox[channel]);
+  item = xbt_fifo_get_first_item(h->simdata->mbox[channel]);
   if (!item || !(t = xbt_fifo_get_item_content(item)))
     return -1;
    
@@ -167,11 +275,118 @@ int MSG_task_probe_from(m_channel_t channel)
 }
 
 /** \ingroup msg_gos_functions
- * \brief Put a task on a channel of an host and waits for the end of the
- * transmission.
+ * \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.
+ *
+ * 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.
+ */
+MSG_error_t MSG_channel_select_from(m_channel_t channel, double max_duration,
+                                   int *PID)
+{
+  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) {
+    *PID = MSG_task_probe_from(channel);
+    MSG_RETURN(MSG_OK);
+  } 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);
+  }
+}
+
+
+/** \ingroup msg_gos_functions
+
+ * \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)
+{
+  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();
+
+  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;
+}
+
+/** \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 three parameter.
+ * 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
@@ -186,64 +401,147 @@ int MSG_task_probe_from(m_channel_t channel)
  * \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 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 
  * \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_put(m_task_t task,
-                        m_host_t dest, m_channel_t channel)
+MSG_error_t MSG_task_put_with_timeout(m_task_t task, m_host_t dest, 
+                                     m_channel_t channel, double max_duration)
 {
   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;
+  int first_time = 1;
 
   CHECK_HOST();
 
+  xbt_assert1((channel>=0) && (channel < msg_global->max_channel),"Invalid channel %d",channel);
+
   task_simdata = task->simdata;
   task_simdata->sender = process;
-  xbt_assert0(task_simdata->using==1,"Gargl!");
+  task_simdata->source = MSG_process_get_host(process);
+  xbt_assert0(task_simdata->using==1,
+             "This taks is still being used somewhere else. You cannot send it now. Go fix your code!");
   task_simdata->comm = NULL;
   
   local_host = ((simdata_process_t) process->simdata)->host;
   remote_host = dest;
 
-  DEBUG4("Trying to send a task (%lg Mb) from %s to %s on channel %d", 
-        task->simdata->message_size,local_host->name, remote_host->name, channel);
+  DEBUG4("Trying to send a task (%g kB) from %s to %s on channel %d", 
+        task->simdata->message_size/1000,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]) 
+  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)) 
-    __MSG_process_block();
+  while(!(task_simdata->comm)) {
+    if(max_duration>0) {
+      if(!first_time) {
+       PAJE_PROCESS_POP_STATE(process);
+       PAJE_COMM_STOP(process,task,channel);
+       MSG_RETURN(MSG_TRANSFER_FAILURE);
+      }
+    }
+    DEBUG0("Communication not initiated yet. Let's block!");
+    if(max_duration>0)
+      __MSG_process_block(max_duration,task->name);
+    else
+      __MSG_process_block(-1,task->name);
+
+    first_time = 0;
+
+    if(surf_workstation_resource->extension_public->
+       get_state(local_host->simdata->host) == SURF_CPU_OFF) {
+      xbt_fifo_remove(((simdata_host_t) remote_host->simdata)->mbox[channel],
+                     task);
+      PAJE_PROCESS_POP_STATE(process);
+      PAJE_COMM_STOP(process,task,channel);
+      MSG_task_destroy(task);
+      MSG_RETURN(MSG_HOST_FAILURE);
+    }
+  }
+  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");  
+  PAJE_PROCESS_PUSH_STATE(process,"C",task);  
 
   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);
   }
-    
-  MSG_task_destroy(task);
+  DEBUG0("Action terminated");
+  task->simdata->rate=-1.0; /* Sets the rate back to default */
 
   PAJE_PROCESS_POP_STATE(process);  
 
-  if(state == SURF_ACTION_DONE) MSG_RETURN(MSG_OK);
-  else if(surf_workstation_resource->extension_public->get_state(local_host->simdata->host) 
-         == SURF_CPU_OFF)
+  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 MSG_RETURN(MSG_TRANSFER_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);
+  }
+}
+/** \ingroup msg_gos_functions
+ * \brief Put a task on a channel of an host and waits for the end of the
+ * transmission.
+ *
+ * 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().
+ * \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().
+ * \return #MSG_FATAL if \a task is not properly initialized and
+ * #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)
+{
+  return MSG_task_put_with_timeout(task, dest, channel, -1.0);
 }
 
 /** \ingroup msg_gos_functions
@@ -256,9 +554,10 @@ 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 res = MSG_OK;
   task->simdata->rate=max_rate;
-  return(MSG_task_put(task, dest, channel));
-  task->simdata->rate=-1.0;
+  res = MSG_task_put(task, dest, channel);
+  return(res);
 }
 
 /** \ingroup msg_gos_functions
@@ -280,7 +579,7 @@ MSG_error_t MSG_task_execute(m_task_t task)
 
   __MSG_task_execute(process, task);
 
-  PAJE_PROCESS_PUSH_STATE(process,"E");  
+  PAJE_PROCESS_PUSH_STATE(process,"E",task);  
   res = __MSG_wait_for_computation(process,task);
   PAJE_PROCESS_POP_STATE(process);
   return res;
@@ -293,11 +592,17 @@ void __MSG_task_execute(m_process_t process, m_task_t task)
   CHECK_HOST();
 
   simdata = task->simdata;
-
+  xbt_assert0((!simdata->compute)&&(task->simdata->using==1),
+             "This taks is executed somewhere else. Go fix your code!");
+  simdata->using++;
   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);
+  simdata->using--;
 }
 
 MSG_error_t __MSG_wait_for_computation(m_process_t process, m_task_t task)
@@ -305,6 +610,7 @@ MSG_error_t __MSG_wait_for_computation(m_process_t process, m_task_t task)
   e_surf_action_state_t state = SURF_ACTION_NOT_IN_THE_SYSTEM;
   simdata_task_t simdata = task->simdata;
 
+  XBT_IN4("(%p(%s) %p(%s))",process,process->name,task,task->name);
   simdata->using++;
   do {
     __MSG_task_wait_event(process, task);
@@ -313,14 +619,119 @@ MSG_error_t __MSG_wait_for_computation(m_process_t process, m_task_t task)
   simdata->using--;
     
 
-  if(state == SURF_ACTION_DONE) MSG_RETURN(MSG_OK);
-  else if(surf_workstation_resource->extension_public->
-         get_state(MSG_process_get_host(process)->simdata->host) 
-         == SURF_CPU_OFF)
+  if(state == SURF_ACTION_DONE) {
+    if(surf_workstation_resource->common_public->action_free(simdata->compute)) 
+      simdata->compute = NULL;
+    simdata->computation_amount = 0.0;
+    XBT_OUT;
+    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;
+    XBT_OUT;
     MSG_RETURN(MSG_HOST_FAILURE);
-  else MSG_RETURN(MSG_TRANSFER_FAILURE);
+  } else {
+    if(surf_workstation_resource->common_public->action_free(simdata->compute)) 
+      simdata->compute = NULL;
+    XBT_OUT;
+    MSG_RETURN(MSG_TASK_CANCELLED);
+  }
+}
+/** \ingroup m_task_management
+ * \brief Creates a new #m_task_t (a parallel one....).
+ *
+ * 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.
+ */
+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)
+{
+  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;
+}
+
+
+static void __MSG_parallel_task_execute(m_process_t process, m_task_t task)
+{
+  simdata_task_t simdata = NULL;
+
+  CHECK_HOST();
+
+  simdata = task->simdata;
+
+  xbt_assert0(simdata->host_nb,"This is not a parallel task. Go to hell.");
+
+  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)
+{
+  m_process_t process = MSG_process_self();
+  MSG_error_t res;
+
+  DEBUG0("Computing on a tons of guys");
+  
+  __MSG_parallel_task_execute(process, task);
+
+  if(task->simdata->compute)
+    res = __MSG_wait_for_computation(process,task);
+  else 
+    res = MSG_OK;
+
+  return res;  
+}
+
+
 /** \ingroup msg_gos_functions
  * \brief Sleep for the specified number of seconds
  *
@@ -334,6 +745,8 @@ MSG_error_t MSG_process_sleep(double nb_sec)
   m_process_t process = MSG_process_self();
   m_task_t dummy = NULL;
   simdata_task_t simdata = NULL;
+  
+  xbt_assert1(nb_sec>=0,"Invalid duration %g",nb_sec);
 
   CHECK_HOST();
   dummy = MSG_task_create("MSG_sleep", nb_sec, 0.0, NULL);
@@ -355,36 +768,46 @@ MSG_error_t MSG_process_sleep(double nb_sec)
   if(state == SURF_ACTION_DONE) {
     if(surf_workstation_resource->extension_public->
        get_state(MSG_process_get_host(process)->simdata->host) 
-       == SURF_CPU_OFF)
+       == 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)
+       == 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);
 }
 
 /** \ingroup msg_gos_functions
- * \brief Return the number of MSG tasks currently running on a
+ * \brief Return the number of MSG tasks currently running on
  * the host of the current running process.
  */
-int MSG_get_msgload(void) 
+static int MSG_get_msgload(void) 
 {
+  m_process_t process;
+   
   CHECK_HOST();
-  xbt_assert0(0,"Not implemented yet!");
   
-  return 1;
+  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);
 }
 
 /** \ingroup msg_gos_functions
  *
- * \brief Return the the last value returned by a MSG function (except
+ * \brief Return the last value returned by a MSG function (except
  * MSG_get_errno...).
  */
 MSG_error_t MSG_get_errno(void)