#include "simgrid/msg.h"
#include "xbt/synchro_core.h"
-XBT_LOG_NEW_DEFAULT_CATEGORY(msg_test, "Messages specific for this msg example");
+XBT_LOG_NEW_DEFAULT_CATEGORY(msg_process_migration, "Messages specific for this msg example");
/** @addtogroup MSG_examples
- *
- * - <b>process-migration/process-migration.c: Process migration example</b>. Demonstrates how to use the
- * @ref MSG_process_migrate function to let processes change the host they run on after their start.
+ *
+ * - <b>Process Migration: process-migration/process-migration.c</b>. Processes can move or be moved from a host to
+ * another while they are running thanks to the @ref MSG_process_migrate function.
*/
-xbt_mutex_t mutex = NULL;
-xbt_cond_t cond = NULL;
-static msg_process_t process_to_migrate = NULL;
+xbt_mutex_t checkpoint = NULL;
+xbt_cond_t identification = NULL;
+static msg_process_t controlled_process = NULL;
-/** The guy we will move from host to host. It move alone and then is moved by policeman back */
+/** The Emigrant will be moved from host to host. */
static int emigrant(int argc, char *argv[])
{
- msg_task_t task;
- XBT_INFO("I'll look for a new job on another machine where the grass is greener.");
- MSG_process_migrate(MSG_process_self(), MSG_host_by_name("Boivin"));
+ XBT_INFO("I'll look for a new job on another machine ('Boivin') where the grass is greener.");
+ MSG_process_migrate(MSG_process_self(), MSG_host_by_name("Boivin")); /** - First, move to another host by myself */
XBT_INFO("Yeah, found something to do");
- task = MSG_task_create("job", 98095000, 0, NULL);
+ msg_task_t task = MSG_task_create("job", 98095000, 0, NULL); /** - Execute some work there */
MSG_task_execute(task);
MSG_task_destroy(task);
MSG_process_sleep(2);
XBT_INFO("Moving back home after work");
- MSG_process_migrate(MSG_process_self(), MSG_host_by_name("Jacquelin"));
- MSG_process_migrate(MSG_process_self(), MSG_host_by_name("Boivin"));
+ MSG_process_migrate(MSG_process_self(), MSG_host_by_name("Jacquelin")); /** - Move back to original location */
+ MSG_process_migrate(MSG_process_self(), MSG_host_by_name("Boivin")); /** - Go back to the other host to sleep*/
MSG_process_sleep(4);
- xbt_mutex_acquire(mutex);
- process_to_migrate = MSG_process_self();
- xbt_cond_broadcast(cond);
- xbt_mutex_release(mutex);
+ xbt_mutex_acquire(checkpoint); /** - Get controlled at checkpoint */
+ controlled_process = MSG_process_self(); /** - and get moved back by @ref policeman */
+ xbt_cond_broadcast(identification);
+ xbt_mutex_release(checkpoint);
MSG_process_suspend(MSG_process_self());
msg_host_t h = MSG_process_get_host(MSG_process_self());
XBT_INFO("I've been moved on this new host: %s", MSG_host_get_name(h));
return 0;
}
-/* This function move the emigrant on Jacquelin */
+/** The policeman check for emigrants and move them back to '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) xbt_cond_wait(cond, mutex);
- MSG_process_migrate(process_to_migrate, MSG_host_by_name("Jacquelin"));
+ xbt_mutex_acquire(checkpoint);
+ XBT_INFO("Wait at the checkpoint."); /** - Wait at @ref checkpoint to control the @ref identification of processes */
+ while (controlled_process == NULL) xbt_cond_wait(identification, checkpoint);
+ MSG_process_migrate(controlled_process, MSG_host_by_name("Jacquelin")); /** - Move an emigrant to Jacquelin */
XBT_INFO("I moved the emigrant");
- MSG_process_resume(process_to_migrate);
- xbt_mutex_release(mutex);
+ MSG_process_resume(controlled_process);
+ xbt_mutex_release(checkpoint);
return 0;
}
MSG_init(&argc, argv);
xbt_assert(argc == 2, "Usage: %s platform_file\n\tExample: %s msg_platform.xml\n", argv[0], argv[0]);
- MSG_create_environment(argv[1]);
-
+ MSG_create_environment(argv[1]); /** - Load the platform description */
+ /** - Create and deploy @ref emigrant and @ref policeman processes */
MSG_process_create("emigrant", emigrant, NULL, MSG_get_host_by_name("Jacquelin"));
MSG_process_create("policeman", policeman, NULL, MSG_get_host_by_name("Boivin"));
- mutex = xbt_mutex_init();
- cond = xbt_cond_init();
- res = MSG_main();
+ checkpoint = xbt_mutex_init(); /** - Initiate @ref checkpoint and @ref identification*/
+ identification = xbt_cond_init();
+ res = MSG_main(); /** - Run the simulation */
XBT_INFO("Simulation time %g", MSG_get_clock());
- xbt_cond_destroy(cond);
- xbt_mutex_destroy(mutex);
+ xbt_cond_destroy(identification);
+ xbt_mutex_destroy(checkpoint);
return res != MSG_OK;
}
