int
ACE_Sched_Params::previous_priority (const Policy policy,
const int priority,
const int scope)
{
#if defined (ACE_HAS_WTHREADS)
ACE_UNUSED_ARG (policy);
ACE_UNUSED_ARG (scope);
switch (priority)
{
case THREAD_PRIORITY_IDLE:
return THREAD_PRIORITY_IDLE;
case THREAD_PRIORITY_LOWEST:
return THREAD_PRIORITY_IDLE;
case THREAD_PRIORITY_BELOW_NORMAL:
return THREAD_PRIORITY_LOWEST;
case THREAD_PRIORITY_NORMAL:
return THREAD_PRIORITY_BELOW_NORMAL;
case THREAD_PRIORITY_ABOVE_NORMAL:
return THREAD_PRIORITY_NORMAL;
case THREAD_PRIORITY_HIGHEST:
return THREAD_PRIORITY_ABOVE_NORMAL;
case THREAD_PRIORITY_TIME_CRITICAL:
return THREAD_PRIORITY_HIGHEST;
default:
return priority; // unknown priority: should never get here
}
#elif defined(ACE_HAS_THREADS) && \
(!defined(ACE_LACKS_SETSCHED) || defined (ACE_TANDEM_T1248_PTHREADS) || \
defined (ACE_HAS_PTHREAD_SCHEDPARAM))
// including STHREADS and PTHREADS
int const min = priority_min (policy, scope);
return priority > min ? priority - 1 : min;
#elif defined (ACE_VXWORKS)
return priority < priority_min (policy, scope)
? priority + 1
: priority_min (policy, scope);
#else
ACE_UNUSED_ARG (policy);
ACE_UNUSED_ARG (scope);
ACE_UNUSED_ARG (priority);
ACE_NOTSUP_RETURN (-1);
#endif /* ACE_HAS_THREADS */
}
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;
}
