int pthread_cond_wait(struct pthread_cond_t *cond, struct mutex_t *mutex)
{
queue_node_t n;
n.priority = sched_active_thread->priority;
n.data = sched_active_thread->pid;
n.next = NULL;
/* the signaling thread may not hold the mutex, the queue is not thread safe */
unsigned old_state = disableIRQ();
queue_priority_add(&(cond->queue), &n);
restoreIRQ(old_state);
mutex_unlock_and_sleep(mutex);
if (n.data != -1u) {
/* on signaling n.data is set to -1u */
/* if it isn't set, then the wakeup is either spurious or a timer wakeup */
old_state = disableIRQ();
queue_remove(&(cond->queue), &n);
restoreIRQ(old_state);
}
mutex_lock(mutex);
return 0;
}
int main(void)
{
indicator = 0;
count = 0;
mutex_init(&mutex);
thread_create(stack,
KERNEL_CONF_STACKSIZE_MAIN,
PRIORITY_MAIN - 1,
CREATE_WOUT_YIELD | CREATE_STACKTEST,
second_thread,
"second_thread");
while (1) {
mutex_lock(&mutex);
thread_wakeup(2);
indicator++;
count++;
if (indicator > 1 || indicator < -1) {
//printf("Error, threads did not sleep properly. [indicator: %d]\n", indicator);
return -1;
}
if ((count % 100000) == 0) {
//printf("Still alive alternated [count: %dk] times.\n", count / 1000);
}
mutex_unlock_and_sleep(&mutex);
}
}
void condition_variable::wait(unique_lock<mutex>& lock) noexcept {
#ifdef NOEXCEPTIONS
lock.owns_lock();
#else
if (!lock.owns_lock()) {
throw std::system_error(
std::make_error_code(std::errc::operation_not_permitted),
"Mutex not locked.");
}
#endif
priority_queue_node_t n;
n.priority = sched_active_thread->priority;
n.data = sched_active_pid;
n.next = NULL;
// the signaling thread may not hold the mutex, the queue is not thread safe
unsigned old_state = disableIRQ();
priority_queue_add(&m_queue, &n);
restoreIRQ(old_state);
mutex_unlock_and_sleep(lock.mutex()->native_handle());
if (n.data != -1u) {
// on signaling n.data is set to -1u
// if it isn't set, then the wakeup is either spurious or a timer wakeup
old_state = disableIRQ();
priority_queue_remove(&m_queue, &n);
restoreIRQ(old_state);
}
mutex_lock(lock.mutex()->native_handle());
}
int main(void)
{
uint32_t count = 0;
indicator = 0;
main_pid = thread_getpid();
kernel_pid_t second_pid = thread_create(stack,
sizeof(stack),
THREAD_PRIORITY_MAIN - 1,
THREAD_CREATE_WOUT_YIELD | THREAD_CREATE_STACKTEST,
second_thread,
NULL,
"second_thread");
while (1) {
mutex_lock(&mutex);
thread_wakeup(second_pid);
indicator++;
count++;
if ((indicator > 1) || (indicator < -1)) {
printf("[ERROR] threads did not sleep properly (%d).\n", indicator);
return 1;
}
if ((count % 100000) == 0) {
printf("[ALIVE] alternated %"PRIu32"k times.\n", (count / 1000));
}
mutex_unlock_and_sleep(&mutex);
}
}
int main(void)
{
indicator = 0;
count = 0;
main_pid = thread_getpid();
kernel_pid_t second_pid = thread_create(stack,
sizeof(stack),
THREAD_PRIORITY_MAIN - 1,
THREAD_CREATE_WOUT_YIELD | THREAD_CREATE_STACKTEST,
second_thread,
NULL,
"second_thread");
while (1) {
mutex_lock(&mutex);
thread_wakeup(second_pid);
indicator++;
count++;
if (indicator > 1 || indicator < -1) {
printf("Error, threads did not sleep properly. [indicator: %d]\n", indicator);
return -1;
}
if ((count % 100000) == 0) {
printf("Still alive alternated [count: %dk] times.\n", count / 1000);
}
mutex_unlock_and_sleep(&mutex);
}
}
static void *run_get(void *arg)
{
(void) arg;
char next = 0;
for (unsigned iteration = 0; iteration < ITERATIONS; ++iteration) {
++next; /* the first element of a stride is always overwritten */
mutex_lock(&mutex);
for (unsigned i = BUF_SIZE; i > 0; --i) {
assert_avail(i);
assert_get_one(next);
assert_avail(i - 1);
++next;
}
assert_avail(0);
assert_get_one(-1);
assert_avail(0);
thread_wakeup(pid_add);
mutex_unlock_and_sleep(&mutex);
}
return NULL;
}
static void run_add(void)
{
char next = 0;
for (unsigned iteration = 0; iteration < ITERATIONS; ++iteration) {
mutex_lock(&mutex);
for (unsigned i = 0; i < BUF_SIZE; ++i) {
assert_avail(i);
assert_add_one(next, -1);
assert_avail(i + 1);
++next;
}
/* Overwrite oldest element. It should be returned to us. */
assert_avail(BUF_SIZE);
assert_add_one(next, next - BUF_SIZE);
assert_avail(BUF_SIZE);
++next;
thread_wakeup(pid_get);
mutex_unlock_and_sleep(&mutex);
}
thread_wakeup(pid_get);
}
static int pthread_rwlock_lock(pthread_rwlock_t *rwlock,
bool (*is_blocked)(const pthread_rwlock_t *rwlock),
bool is_writer,
int incr_when_held,
bool allow_spurious)
{
if (rwlock == NULL) {
DEBUG("Thread %" PRIkernel_pid": pthread_rwlock_%s(): is_writer=%u, allow_spurious=%u %s\n",
thread_getpid(), "lock", is_writer, allow_spurious, "rwlock=NULL");
return EINVAL;
}
mutex_lock(&rwlock->mutex);
if (!is_blocked(rwlock)) {
DEBUG("Thread %" PRIkernel_pid ": pthread_rwlock_%s(): is_writer=%u, allow_spurious=%u %s\n",
thread_getpid(), "lock", is_writer, allow_spurious, "is open");
rwlock->readers += incr_when_held;
}
else {
DEBUG("Thread %" PRIkernel_pid ": pthread_rwlock_%s(): is_writer=%u, allow_spurious=%u %s\n",
thread_getpid(), "lock", is_writer, allow_spurious, "is locked");
/* queue for the lock */
__pthread_rwlock_waiter_node_t waiting_node = {
.is_writer = is_writer,
.thread = (thread_t *) sched_active_thread,
.qnode = {
.next = NULL,
.data = (uintptr_t) &waiting_node,
.priority = sched_active_thread->priority,
},
.continue_ = false,
};
priority_queue_add(&rwlock->queue, &waiting_node.qnode);
while (1) {
/* wait to be unlocked, so this thread can try to acquire the lock again */
mutex_unlock_and_sleep(&rwlock->mutex);
mutex_lock(&rwlock->mutex);
if (waiting_node.continue_) {
/* pthread_rwlock_unlock() already set rwlock->readers */
DEBUG("Thread %" PRIkernel_pid ": pthread_rwlock_%s(): is_writer=%u, allow_spurious=%u %s\n",
thread_getpid(), "lock", is_writer, allow_spurious, "continued");
break;
}
else if (allow_spurious) {
DEBUG("Thread %" PRIkernel_pid ": pthread_rwlock_%s(): is_writer=%u, allow_spurious=%u %s\n",
thread_getpid(), "lock", is_writer, allow_spurious, "is timed out");
priority_queue_remove(&rwlock->queue, &waiting_node.qnode);
mutex_unlock(&rwlock->mutex);
return ETIMEDOUT;
}
}
}
mutex_unlock(&rwlock->mutex);
return 0;
}
static void second_thread(void)
{
while (1) {
mutex_lock(&mutex);
thread_wakeup(1);
indicator--;
mutex_unlock_and_sleep(&mutex);
}
}
static void *second_thread(void *arg)
{
(void) arg;
while (1) {
mutex_lock(&mutex);
thread_wakeup(main_pid);
indicator--;
mutex_unlock_and_sleep(&mutex);
}
return NULL;
}
/**
* @brief This thread tries to lock the mutex to enter the critical section.
* Then it signals one waiting thread to check the condition and it goes to sleep again
* If is_finished is set to 1 second_thread ends
*/
static void *second_thread(void *arg)
{
(void) arg;
while (1) {
mutex_lock(&mutex);
if (is_finished == 1) {
break;
}
pthread_cond_signal(&cv);
mutex_unlock_and_sleep(&mutex);
}
return NULL;
}
int pthread_barrier_wait(pthread_barrier_t *barrier)
{
/* Idea: the count is decreased by every thread that waits on the barrier.
* If the value is bigger than zero afterwards, then the thread has to wait
* to be woken up. Once the value reaches zero, everyone gets woken up. */
mutex_lock(&barrier->mutex);
DEBUG("%s: hit a synchronization barrier. pid=%" PRIkernel_pid"\n",
sched_active_thread->name, sched_active_pid);
int switch_prio = -1;
if (--barrier->count > 0) {
/* need to wait for further threads */
DEBUG("%s: waiting for %u threads. pid=%" PRIkernel_pid "\n",
sched_active_thread->name, barrier->count, sched_active_pid);
pthread_barrier_waiting_node_t node;
node.pid = sched_active_pid;
node.next = barrier->next;
node.cont = 0;
barrier->next = &node;
mutex_unlock(&barrier->mutex);
while (1) {
/* The mutex is reacquired before checking if we should continue,
* so that the waiting thread don't accidentially run before the
* wake up loop has ended. Otherwise the thread could run into the
* the barrier again before `barrier->count` was reset. */
mutex_lock(&barrier->mutex);
if (node.cont) {
break;
}
mutex_unlock_and_sleep(&barrier->mutex);
}
}
else {
/* all threads have arrived, wake everybody up */
DEBUG("%s: waking every other thread up. pid=%" PRIkernel_pid "\n",
sched_active_thread->name, sched_active_pid);
int count = 1; /* Count number of woken up threads.
* The first thread is the current thread. */
pthread_barrier_waiting_node_t *next;
for (next = barrier->next; next; next = next->next) {
++count;
next->cont = 1;
thread_t *other = (thread_t *) sched_threads[next->pid];
switch_prio = priority_min(switch_prio, other->priority);
sched_set_status(other, STATUS_PENDING);
}
barrier->next = NULL;
barrier->count = count;
}
mutex_unlock(&barrier->mutex);
if (switch_prio != -1) {
sched_switch(switch_prio);
}
return 0;
}
