-/* $Id$ */
-
-/* Copyright (c) 2007 Arnaud Legrand, Bruno Donnassolo.
- All rights reserved. */
+/* Copyright (c) 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. */
XBT_LOG_NEW_DEFAULT_SUBCATEGORY(simix_synchro, simix,
- "Logging specific to SIMIX (synchronization)");
+ "Logging specific to SIMIX (synchronization)");
/****************************** Synchronization *******************************/
*/
smx_mutex_t SIMIX_mutex_init()
{
- smx_mutex_t m = xbt_new0(s_smx_mutex_t,1);
- s_smx_process_t p; /* useful to initialize sleeping swag */
- /* structures initialization */
- m->using = 0;
- m->sleeping = xbt_swag_new(xbt_swag_offset(p, synchro_hookup));
- return m;
+ smx_mutex_t m = xbt_new0(s_smx_mutex_t, 1);
+ s_smx_process_t p; /* useful to initialize sleeping swag */
+ /* structures initialization */
+ m->refcount = 0;
+ m->sleeping = xbt_swag_new(xbt_swag_offset(p, synchro_hookup));
+ return m;
}
/**
*/
void SIMIX_mutex_lock(smx_mutex_t mutex)
{
- smx_process_t self = SIMIX_process_self();
- xbt_assert0((mutex != NULL), "Invalid parameters");
-
-
- if (mutex->using) {
- /* somebody using the mutex, block */
- xbt_swag_insert(self, mutex->sleeping);
- self->simdata->mutex = mutex;
- /* wait for some process make the unlock and wake up me from mutex->sleeping */
- xbt_context_yield();
- self->simdata->mutex = NULL;
-
- /* verify if the process was suspended */
- while (self->simdata->suspended) {
- xbt_context_yield();
- }
-
- mutex->using = 1;
- }
- else {
- /* mutex free */
- mutex->using = 1;
- }
- return;
+ smx_process_t self = SIMIX_process_self();
+ xbt_assert0((mutex != NULL), "Invalid parameters");
+
+
+ if (mutex->refcount) {
+ /* somebody using the mutex, block */
+ xbt_swag_insert(self, mutex->sleeping);
+ self->mutex = mutex;
+ /* wait for some process make the unlock and wake up me from mutex->sleeping */
+ SIMIX_process_yield();
+ self->mutex = NULL;
+
+ /* verify if the process was suspended */
+ while (self->suspended) {
+ SIMIX_process_yield();
+ }
+
+ mutex->refcount = 1;
+ } else {
+ /* mutex free */
+ mutex->refcount = 1;
+ }
+ return;
}
/**
* \param mutex The mutex
* \return 1 - mutex free, 0 - mutex used
*/
-int SIMIX_mutex_trylock(smx_mutex_t mutex)
+XBT_INLINE int SIMIX_mutex_trylock(smx_mutex_t mutex)
{
- xbt_assert0((mutex != NULL), "Invalid parameters");
-
- if (mutex->using)
- return 0;
- else {
- mutex->using = 1;
- return 1;
- }
+ xbt_assert0((mutex != NULL), "Invalid parameters");
+
+ if (mutex->refcount)
+ return 0;
+ else {
+ mutex->refcount = 1;
+ return 1;
+ }
}
/**
*/
void SIMIX_mutex_unlock(smx_mutex_t mutex)
{
- smx_process_t p; /*process to wake up */
-
- xbt_assert0((mutex != NULL), "Invalid parameters");
-
- if (xbt_swag_size(mutex->sleeping) > 0) {
- p = xbt_swag_extract(mutex->sleeping);
- mutex->using = 0;
- xbt_swag_insert(p, simix_global->process_to_run);
- }
- else {
- /* nobody to wake up */
- mutex->using = 0;
- }
- return;
+ smx_process_t p; /*process to wake up */
+
+ xbt_assert0((mutex != NULL), "Invalid parameters");
+
+ if (xbt_swag_size(mutex->sleeping) > 0) {
+ p = xbt_swag_extract(mutex->sleeping);
+ mutex->refcount = 0;
+ xbt_swag_insert(p, simix_global->process_to_run);
+ } else {
+ /* nobody to wake up */
+ mutex->refcount = 0;
+ }
+ return;
}
/**
* Destroys and frees the mutex's memory.
* \param mutex A mutex
*/
-void SIMIX_mutex_destroy(smx_mutex_t mutex)
+XBT_INLINE void SIMIX_mutex_destroy(smx_mutex_t mutex)
{
- if ( mutex == NULL )
- return ;
- else {
- xbt_swag_free(mutex->sleeping);
- xbt_free(mutex);
- return ;
- }
+ if (mutex == NULL)
+ return;
+ else {
+ xbt_swag_free(mutex->sleeping);
+ xbt_free(mutex);
+ return;
+ }
}
/******************************** Conditional *********************************/
/**
* \brief Initialize a condition.
*
- * Allocs and creates the data for the condition. It have to be called before the utilisation of the condition.
+ * Allocates and creates the data for the condition.
+ * It have to be called before the use of the condition.
* \return A condition
*/
smx_cond_t SIMIX_cond_init()
{
- smx_cond_t cond = xbt_new0(s_smx_cond_t,1);
- s_smx_process_t p;
-
- cond->sleeping = xbt_swag_new(xbt_swag_offset(p,synchro_hookup));
- cond->actions = xbt_fifo_new();
- cond->mutex = NULL;
- return cond;
+ smx_cond_t cond = xbt_new0(s_smx_cond_t, 1);
+ s_smx_process_t p;
+
+ cond->sleeping = xbt_swag_new(xbt_swag_offset(p, synchro_hookup));
+ cond->actions = xbt_fifo_new();
+ cond->mutex = NULL;
+ return cond;
}
/**
* \brief Signalizes a condition.
*
- * Signalizes a condition and wakes up a sleping process. If there are no process sleeping, no action is done.
+ * Signalizes a condition and wakes up a sleeping process. If there are no process sleeping, no action is done.
* \param cond A condition
*/
void SIMIX_cond_signal(smx_cond_t cond)
{
- xbt_assert0((cond != NULL), "Invalid parameters");
- smx_process_t proc = NULL;
+ smx_process_t proc = NULL;
+ DEBUG1("Signal condition %p", cond);
+ xbt_assert0((cond != NULL), "Invalid parameters");
- if (xbt_swag_size(cond->sleeping) >= 1) {
- proc = xbt_swag_extract(cond->sleeping);
- xbt_swag_insert(proc, simix_global->process_to_run);
- }
- return;
+ if (xbt_swag_size(cond->sleeping) >= 1) {
+ proc = xbt_swag_extract(cond->sleeping);
+ xbt_swag_insert(proc, simix_global->process_to_run);
+ }
+
+ return;
}
/**
* \param cond A condition
* \param mutex A mutex
*/
-void SIMIX_cond_wait(smx_cond_t cond,smx_mutex_t mutex)
+void SIMIX_cond_wait(smx_cond_t cond, smx_mutex_t mutex)
{
- smx_action_t act_sleep;
- xbt_assert0((mutex != NULL), "Invalid parameters");
-
- cond->mutex = mutex;
-
- SIMIX_mutex_unlock(mutex);
- /* create an action null only if there are no actions already on the condition, usefull if the host crashs */
- if (xbt_fifo_size(cond->actions) ==0 ) {
- act_sleep = SIMIX_action_sleep(SIMIX_host_self(), -1);
- SIMIX_register_action_to_condition(act_sleep,cond);
- SIMIX_register_condition_to_action(act_sleep,cond);
- __SIMIX_cond_wait(cond);
- xbt_fifo_pop(act_sleep->cond_list);
- SIMIX_action_destroy(act_sleep);
- }
- else {
- __SIMIX_cond_wait(cond);
- }
- /* get the mutex again */
- SIMIX_mutex_lock(cond->mutex);
-
- return;
+ smx_action_t act_sleep;
+
+ DEBUG1("Wait condition %p", cond);
+
+ /* If there is a mutex unlock it */
+ if (mutex != NULL) {
+ cond->mutex = mutex;
+ SIMIX_mutex_unlock(mutex);
+ }
+
+ /* Always create an action null in case there is a host failure */
+ act_sleep = SIMIX_action_sleep(SIMIX_host_self(), -1);
+ SIMIX_action_set_name(act_sleep, bprintf("Wait condition %p", cond));
+ SIMIX_process_self()->waiting_action = act_sleep;
+ SIMIX_register_action_to_condition(act_sleep, cond);
+ __SIMIX_cond_wait(cond);
+ SIMIX_process_self()->waiting_action = NULL;
+ SIMIX_unregister_action_to_condition(act_sleep, cond);
+ SIMIX_action_destroy(act_sleep);
+
+ /* get the mutex again if necessary */
+ if (mutex != NULL)
+ SIMIX_mutex_lock(cond->mutex);
+
+ return;
}
-xbt_fifo_t SIMIX_cond_get_actions(smx_cond_t cond)
+XBT_INLINE xbt_fifo_t SIMIX_cond_get_actions(smx_cond_t cond)
{
- xbt_assert0((cond != NULL), "Invalid parameters");
- return cond->actions;
+ xbt_assert0((cond != NULL), "Invalid parameters");
+ return cond->actions;
}
void __SIMIX_cond_wait(smx_cond_t cond)
{
- smx_process_t self = SIMIX_process_self();
- xbt_assert0((cond != NULL), "Invalid parameters");
-
- /* process status */
-
- self->simdata->cond = cond;
- xbt_swag_insert(self, cond->sleeping);
- xbt_context_yield();
- self->simdata->cond = NULL;
- while (self->simdata->suspended) {
- xbt_context_yield();
- }
- return;
-
+ smx_process_t self = SIMIX_process_self();
+ xbt_assert0((cond != NULL), "Invalid parameters");
+
+ /* process status */
+
+ self->cond = cond;
+ xbt_swag_insert(self, cond->sleeping);
+ SIMIX_process_yield();
+ self->cond = NULL;
+ while (self->suspended) {
+ SIMIX_process_yield();
+ }
+ return;
}
/**
* \brief Waits on a condition with timeout.
*
- * Same behavior of #SIMIX_cond_wait, but waits a maximum time.
+ * Same behavior of #SIMIX_cond_wait, but waits a maximum time and throws an timeout_error if it happens.
* \param cond A condition
* \param mutex A mutex
* \param max_duration Timeout time
*/
-void SIMIX_cond_wait_timeout(smx_cond_t cond,smx_mutex_t mutex, double max_duration)
+void SIMIX_cond_wait_timeout(smx_cond_t cond, smx_mutex_t mutex,
+ double max_duration)
{
- xbt_assert0((mutex != NULL), "Invalid parameters");
- smx_action_t act_sleep;
-
- cond->mutex = mutex;
-
- SIMIX_mutex_unlock(mutex);
- if (max_duration >=0) {
- act_sleep = SIMIX_action_sleep(SIMIX_host_self(), max_duration);
- SIMIX_register_action_to_condition(act_sleep,cond);
- SIMIX_register_condition_to_action(act_sleep,cond);
- __SIMIX_cond_wait(cond);
- xbt_fifo_remove(act_sleep->cond_list,cond);
- SIMIX_action_destroy(act_sleep);
- }
- else
- __SIMIX_cond_wait(cond);
-
- /* get the mutex again */
- SIMIX_mutex_lock(cond->mutex);
-
- return;
+ smx_action_t act_sleep;
+
+ DEBUG1("Timed wait condition %p", cond);
+
+ /* If there is a mutex unlock it */
+ if (mutex != NULL) {
+ cond->mutex = mutex;
+ SIMIX_mutex_unlock(mutex);
+ }
+
+ if (max_duration >= 0) {
+ act_sleep = SIMIX_action_sleep(SIMIX_host_self(), max_duration);
+ SIMIX_action_set_name(act_sleep,
+ bprintf
+ ("Timed wait condition %p (max_duration:%f)",
+ cond, max_duration));
+ SIMIX_register_action_to_condition(act_sleep, cond);
+ SIMIX_process_self()->waiting_action = act_sleep;
+ __SIMIX_cond_wait(cond);
+ SIMIX_process_self()->waiting_action = NULL;
+ SIMIX_unregister_action_to_condition(act_sleep, cond);
+ if (SIMIX_action_get_state(act_sleep) == SURF_ACTION_DONE) {
+ SIMIX_action_destroy(act_sleep);
+ THROW1(timeout_error, 0, "Condition timeout after %f", max_duration);
+ } else {
+ SIMIX_action_destroy(act_sleep);
+ }
+
+ } else
+ SIMIX_cond_wait(cond, NULL);
+
+ /* get the mutex again if necessary */
+ if (mutex != NULL)
+ SIMIX_mutex_lock(cond->mutex);
}
/**
*/
void SIMIX_cond_broadcast(smx_cond_t cond)
{
- xbt_assert0((cond != NULL), "Invalid parameters");
- smx_process_t proc = NULL;
- smx_process_t proc_next = NULL;
+ smx_process_t proc = NULL;
+ smx_process_t proc_next = NULL;
- xbt_swag_foreach_safe(proc,proc_next,cond->sleeping) {
- xbt_swag_remove(proc,cond->sleeping);
- xbt_swag_insert(proc, simix_global->process_to_run);
- }
+ xbt_assert0((cond != NULL), "Invalid parameters");
- return;
+ DEBUG1("Broadcast condition %p", cond);
+ xbt_swag_foreach_safe(proc, proc_next, cond->sleeping) {
+ xbt_swag_remove(proc, cond->sleeping);
+ xbt_swag_insert(proc, simix_global->process_to_run);
+ }
}
/**
*/
void SIMIX_cond_destroy(smx_cond_t cond)
{
- if ( cond == NULL )
- return ;
- else {
- xbt_assert0( xbt_swag_size(cond->sleeping) == 0 , "Cannot destroy conditional");
- xbt_swag_free(cond->sleeping);
- xbt_fifo_free(cond->actions);
- xbt_free(cond);
- return;
- }
+ DEBUG1("Destroy condition %p", cond);
+ if (cond == NULL)
+ return;
+ else {
+ xbt_fifo_item_t item = NULL;
+ smx_action_t action = NULL;
+
+ xbt_assert0(xbt_swag_size(cond->sleeping) == 0,
+ "Cannot destroy conditional since someone is still using it");
+ xbt_swag_free(cond->sleeping);
+
+ DEBUG1("%d actions registered", xbt_fifo_size(cond->actions));
+ __SIMIX_cond_display_actions(cond);
+ xbt_fifo_foreach(cond->actions, item, action, smx_action_t) {
+ SIMIX_unregister_action_to_condition(action, cond);
+ }
+ __SIMIX_cond_display_actions(cond);
+
+ xbt_fifo_free(cond->actions);
+ xbt_free(cond);
+ return;
+ }
+}
+
+void SIMIX_cond_display_info(smx_cond_t cond)
+{
+ if (cond == NULL)
+ return;
+ else {
+ smx_process_t process = NULL;
+
+ INFO0("Blocked process on this condition:");
+ xbt_swag_foreach(process, cond->sleeping) {
+ INFO2("\t %s running on host %s", process->name,
+ process->smx_host->name);
+ }
+ }
+}
+
+/* ************************** Semaphores ************************************** */
+#define SMX_SEM_NOLIMIT 99999
+/** @brief Initialize a semaphore */
+smx_sem_t SIMIX_sem_init(int capacity)
+{
+ smx_sem_t sem = xbt_new0(s_smx_sem_t, 1);
+
+ sem->sleeping = xbt_fifo_new();
+ sem->actions = xbt_fifo_new();
+ sem->capacity = capacity;
+ return sem;
+}
+
+/** @brief Destroys a semaphore */
+void SIMIX_sem_destroy(smx_sem_t sem)
+{
+ smx_action_t action = NULL;
+ DEBUG1("Destroy semaphore %p", sem);
+ if (sem == NULL)
+ return;
+
+ xbt_assert0(xbt_fifo_size(sem->sleeping) == 0,
+ "Cannot destroy semaphore since someone is still using it");
+ xbt_fifo_free(sem->sleeping);
+
+ DEBUG1("%d actions registered", xbt_fifo_size(sem->actions));
+ while ((action = xbt_fifo_pop(sem->actions)))
+ SIMIX_unregister_action_to_semaphore(action, sem);
+
+ xbt_fifo_free(sem->actions);
+ xbt_free(sem);
+}
+
+/** @brief release the semaphore
+ *
+ * The first locked process on this semaphore is unlocked.
+ * If no one was blocked, the semaphore capacity is increased by 1.
+ * */
+void SIMIX_sem_release(smx_sem_t sem)
+{
+ smx_process_t proc;
+
+ if (sem->capacity != SMX_SEM_NOLIMIT) {
+ sem->capacity++;
+ }
+ DEBUG1("Sem release semaphore %p", sem);
+ if ((proc = xbt_fifo_shift(sem->sleeping)) != NULL) {
+ xbt_swag_insert(proc, simix_global->process_to_run);
+ }
+}
+
+/** @brief make sure the semaphore will never be blocking again
+ *
+ * This function is not really in the semaphore spirit. It makes
+ * sure that the semaphore will never be blocking anymore.
+ *
+ * Releasing and acquiring the semaphore after calling this
+ * function is a noop. Such "broken" semaphores are useful to
+ * implement something between condition variables (with broadcast)
+ * and semaphore (with memory). It's like a semaphore signaled for ever.
+ *
+ * There is no way to reset the semaphore to a more regular state afterward.
+ * */
+void SIMIX_sem_release_forever(smx_sem_t sem)
+{
+ smx_process_t proc;
+
+ sem->capacity = SMX_SEM_NOLIMIT;
+ DEBUG1("Broadcast semaphore %p", sem);
+ while ((proc = xbt_fifo_shift(sem->sleeping)) != NULL) {
+ xbt_swag_insert(proc, simix_global->process_to_run);
+ }
}
/**
- * \brief Set a condition to an action
+ * \brief Low level wait on a semaphore
*
- * Creates the "link" between an action and a condition. You have to call this function when you create an action and want to wait its ending.
- * \param action SIMIX action
- * \param cond SIMIX cond
+ * This function does not test the capacity of the semaphore and direcly locks
+ * the calling process on the semaphore (until someone call SIMIX_sem_release()
+ * on this semaphore). Do not call this function if you did not attach any action
+ * to this semaphore to be awaken. Note also that you may miss host failure if you
+ * do not attach a dummy action beforehand. SIMIX_sem_acquire does all these
+ * things for you so you it may be preferable to use.
*/
-void SIMIX_register_condition_to_action(smx_action_t action, smx_cond_t cond)
+void SIMIX_sem_block_onto(smx_sem_t sem)
{
- xbt_assert0( (action != NULL) && (cond != NULL), "Invalid parameters");
+ smx_process_t self = SIMIX_process_self();
+
+ /* process status */
+ self->sem = sem;
+ xbt_fifo_push(sem->sleeping, self);
+ SIMIX_process_yield();
+ self->sem = NULL;
+ while (self->suspended)
+ SIMIX_process_yield();
+}
- xbt_fifo_push(action->cond_list,cond);
+/** @brief Returns true if acquiring this semaphore would block */
+XBT_INLINE int SIMIX_sem_would_block(smx_sem_t sem)
+{
+ return (sem->capacity <= 0);
+}
+
+/** @brief Returns the current capacity of the semaphore
+ *
+ * If it's negative, that's the amount of processes locked on the semaphore
+ */
+int SIMIX_sem_get_capacity(smx_sem_t sem)
+{
+ return sem->capacity;
+}
+
+/**
+ * \brief Waits on a semaphore
+ *
+ * If the capacity>0, decrease the capacity.
+ *
+ * If capacity==0, locks the current process
+ * until someone call SIMIX_sem_release() on this semaphore
+ */
+void SIMIX_sem_acquire(smx_sem_t sem)
+{
+ SIMIX_sem_acquire_timeout(sem, -1);
}
+/**
+ * \brief Tries to acquire a semaphore before a timeout
+ *
+ * Same behavior of #SIMIX_sem_acquire, but waits a maximum time and throws an timeout_error if it happens.
+ */
+void SIMIX_sem_acquire_timeout(smx_sem_t sem, double max_duration)
+{
+ smx_action_t act_sleep;
+
+ DEBUG2("Wait semaphore %p (timeout:%f)", sem, max_duration);
+
+ if (sem->capacity == SMX_SEM_NOLIMIT) {
+ DEBUG1("semaphore %p wide open", sem);
+ return; /* don't even decrease it if wide open */
+ }
+
+ /* If capacity sufficient, decrease it */
+ if (sem->capacity > 0) {
+ DEBUG1("semaphore %p has enough capacity", sem);
+ sem->capacity--;
+ return;
+ }
+
+ /* Always create an action null in case there is a host failure */
+ act_sleep = SIMIX_action_sleep(SIMIX_host_self(), max_duration);
+ SIMIX_action_set_name(act_sleep,
+ bprintf("Locked in semaphore %p (max_duration:%f)",
+ sem, max_duration));
+ SIMIX_process_self()->waiting_action = act_sleep;
+ SIMIX_register_action_to_semaphore(act_sleep, sem);
+ SIMIX_sem_block_onto(sem);
+ SIMIX_process_self()->waiting_action = NULL;
+ SIMIX_unregister_action_to_semaphore(act_sleep, sem);
+ if (max_duration >= 0
+ && SIMIX_action_get_state(act_sleep) == SURF_ACTION_DONE) {
+ SIMIX_action_destroy(act_sleep);
+ THROW1(timeout_error, 0, "Semaphore acquire timeouted after %f",
+ max_duration);
+ } else {
+ if (sem->capacity != SMX_SEM_NOLIMIT) {
+ /* Take the released token */
+ sem->capacity--;
+ }
+ SIMIX_action_destroy(act_sleep);
+ }
+ DEBUG1("End of Wait on semaphore %p", sem);
+}
+/**
+ * \brief Blocks on a set of semaphore
+ *
+ * If any of the semaphores has some more capacity, it gets decreased.
+ * If not, blocks until the capacity of one of the semaphores becomes more friendly.
+ *
+ * \return the rank in the dynar of the semaphore which just got locked from the set
+ */
+unsigned int SIMIX_sem_acquire_any(xbt_dynar_t sems)
+{
+ smx_sem_t sem;
+ unsigned int counter, result = -1;
+ smx_action_t act_sleep;
+ smx_process_t self = SIMIX_process_self();
+
+ xbt_assert0(xbt_dynar_length(sems),
+ "I refuse to commit sucide by locking on an **empty** set of semaphores!!");
+ DEBUG2("Wait on semaphore set %p (containing %ld semaphores)", sems,
+ xbt_dynar_length(sems));
+
+ xbt_dynar_foreach(sems, counter, sem) {
+ if (!SIMIX_sem_would_block(sem)) {
+ DEBUG1("Semaphore %p wouldn't block; get it without waiting", sem);
+ SIMIX_sem_acquire(sem);
+ return counter;
+ }
+ }
+
+ /* Always create an action null in case there is a host failure */
+ act_sleep = SIMIX_action_sleep(SIMIX_host_self(), -1);
+ SIMIX_action_set_name(act_sleep, bprintf("Locked in semaphore %p", sem));
+ self->waiting_action = act_sleep;
+ SIMIX_register_action_to_semaphore(act_sleep,
+ xbt_dynar_get_as(sems, 0, smx_sem_t));
+
+ /* Get listed as member of all the provided semaphores */
+ self->sem = (smx_sem_t) sems; /* FIXME: we pass a pointer to dynar where a pointer to sem is expected... */
+ xbt_dynar_foreach(sems, counter, sem) {
+ xbt_fifo_push(sem->sleeping, self);
+ }
+ SIMIX_process_yield();
+ self->sem = NULL;
+ while (self->suspended)
+ SIMIX_process_yield();
+
+ /* at least one of the semaphore unsuspended us -- great, let's search the first one (and get out of the others) */
+ xbt_dynar_foreach(sems, counter, sem) {
+ if (!xbt_fifo_remove(sem->sleeping, self) && result == -1) {
+ if (sem->capacity != SMX_SEM_NOLIMIT) {
+ /* Take the released token */
+ sem->capacity--;
+ }
+ result = counter;
+ }
+ }
+ xbt_assert0(result != -1, "Cannot find which semaphore unlocked me!");
+
+ /* Destroy the waiting action */
+ self->waiting_action = NULL;
+ SIMIX_unregister_action_to_semaphore(act_sleep,
+ xbt_dynar_get_as(sems, 0,
+ smx_sem_t));
+ SIMIX_action_destroy(act_sleep);
+ return result;
+}
