Make this example insensitive to scheduling order of events occuring at the same...

At time 7, depending whether the policeman is waken up before or after the emigrant, the migration could take place either at time 7 or at time 8.

diff --git a/examples/msg/migration/migration.c b/examples/msg/migration/migration.c
index 2fc714d..cd2b65d 100644 (file)
--- a/examples/msg/migration/migration.c
+++ b/examples/msg/migration/migration.c
@@ -12,6 +12,8 @@
 XBT_LOG_NEW_DEFAULT_CATEGORY(msg_test,
                              "Messages specific for this msg example");
 
+xbt_mutex_t mutex = NULL;
+xbt_cond_t cond = NULL;
 static m_process_t process_to_migrate = NULL;
 
 /** The guy we will move from host to host. It move alone and then is moved by policeman back  */
@@ -31,7 +33,10 @@ static int emigrant(int argc, char *argv[])
   MSG_process_migrate(MSG_process_self(), MSG_get_host_by_name("Jacquelin"));
   MSG_process_migrate(MSG_process_self(), MSG_get_host_by_name("Boivin"));
   MSG_process_sleep(4);
+  xbt_mutex_acquire(mutex);
   process_to_migrate = MSG_process_self();
+  xbt_cond_broadcast(cond);
+  xbt_mutex_release(mutex);
   MSG_process_suspend(MSG_process_self());
   m_host_t h = MSG_process_get_host(MSG_process_self());
   XBT_INFO("I've been moved on this new host: %s", h->name);
@@ -43,11 +48,15 @@ static int emigrant(int argc, char *argv[])
 /* This function move the emigrant on Jacquelin */
 static int policeman(int argc, char *argv[])
 {
+
+  xbt_mutex_acquire(mutex);
   XBT_INFO("Wait a bit before migrating the emigrant.");
-  while (process_to_migrate == NULL) MSG_process_sleep(1);
+  while (process_to_migrate == NULL) xbt_cond_wait(cond, mutex);
   MSG_process_migrate(process_to_migrate, MSG_get_host_by_name("Jacquelin"));
   XBT_INFO("I moved the emigrant");
   MSG_process_resume(process_to_migrate);
+  xbt_mutex_release(mutex);
+
   return 0;
 }                               /* end_of_policeman */
 
@@ -75,8 +84,13 @@ int main(int argc, char *argv[])
   MSG_launch_application(argv[2]);
 
   /* Run the simulation */
+  mutex = xbt_mutex_init();
+  cond = xbt_cond_init();
   res = MSG_main();
   XBT_INFO("Simulation time %g", MSG_get_clock());
+  xbt_cond_destroy(cond);
+  xbt_mutex_destroy(mutex);
+
   if (res == MSG_OK)
     res = MSG_clean();