-/* $Id$ */
-
-/* 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_swag_insert(self, mutex->sleeping);
self->mutex = mutex;
/* wait for some process make the unlock and wake up me from mutex->sleeping */
- xbt_context_yield();
+ SIMIX_process_yield();
self->mutex = NULL;
/* verify if the process was suspended */
while (self->suspended) {
- xbt_context_yield();
+ SIMIX_process_yield();
}
mutex->refcount = 1;
* \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");
* 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;
/**
* \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()
void SIMIX_cond_wait(smx_cond_t cond, smx_mutex_t mutex)
{
smx_action_t act_sleep;
- xbt_assert0((mutex != NULL), "Invalid parameters");
DEBUG1("Wait condition %p", cond);
- cond->mutex = mutex;
- SIMIX_mutex_unlock(mutex);
- /* always create an action null in case there is a host failure */
-/* if (xbt_fifo_size(cond->actions) == 0) { */
+ /* 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);
-/* } else { */
-/* __SIMIX_cond_wait(cond); */
-/* } */
- /* get the mutex again */
- SIMIX_mutex_lock(cond->mutex);
+
+ /* 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;
self->cond = cond;
xbt_swag_insert(self, cond->sleeping);
- xbt_context_yield();
+ SIMIX_process_yield();
self->cond = NULL;
while (self->suspended) {
- xbt_context_yield();
+ SIMIX_process_yield();
}
return;
-
}
/**
void SIMIX_cond_wait_timeout(smx_cond_t cond, smx_mutex_t mutex,
double max_duration)
{
-
smx_action_t act_sleep;
- xbt_assert0((mutex != NULL), "Invalid parameters");
DEBUG1("Timed wait condition %p", cond);
- cond->mutex = mutex;
- SIMIX_mutex_unlock(mutex);
+ /* 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);
- THROW0(timeout_error, 0, "Condition timeout");
+ THROW1(timeout_error, 0, "Condition timeout after %f", max_duration);
} else {
SIMIX_action_destroy(act_sleep);
}
} else
- __SIMIX_cond_wait(cond);
-
- /* get the mutex again */
- SIMIX_mutex_lock(cond->mutex);
+ SIMIX_cond_wait(cond, NULL);
- return;
+ /* get the mutex again if necessary */
+ if (mutex != NULL)
+ SIMIX_mutex_lock(cond->mutex);
}
/**
xbt_swag_remove(proc, cond->sleeping);
xbt_swag_insert(proc, simix_global->process_to_run);
}
-
- return;
}
/**
}
}
}
+
+/* ************************** 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 Low level wait on a semaphore
+ *
+ * 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_sem_block_onto(smx_sem_t sem)
+{
+ 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();
+}
+
+/** @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;
+}
