void scheduler_schedule(void)
{
TID_t t;
thread_table_t *current_thread;
int this_cpu;
this_cpu = _interrupt_getcpu();
spinlock_acquire(&thread_table_slock);
current_thread = &(thread_table[scheduler_current_thread[this_cpu]]);
if(current_thread->state == THREAD_DYING) {
current_thread->state = THREAD_FREE;
} else if(current_thread->sleeps_on != 0) {
current_thread->state = THREAD_SLEEPING;
} else {
if(scheduler_current_thread[this_cpu] != IDLE_THREAD_TID)
scheduler_add_to_ready_list(scheduler_current_thread[this_cpu]);
current_thread->state = THREAD_READY;
}
t = scheduler_remove_first_ready();
thread_table[t].state = THREAD_RUNNING;
spinlock_release(&thread_table_slock);
scheduler_current_thread[this_cpu] = t;
/* Schedule timer interrupt to occur after thread timeslice is spent */
timer_set_ticks(_get_rand(CONFIG_SCHEDULER_TIMESLICE) +
CONFIG_SCHEDULER_TIMESLICE / 2);
}
void scheduler_schedule(void)
{
TID_t t;
TID_t lowestDL = -1;
thread_table_t *current_thread;
int this_cpu;
this_cpu = _interrupt_getcpu();
spinlock_acquire(&thread_table_slock);
current_thread = &(thread_table[scheduler_current_thread[this_cpu]]);
if(current_thread->state == THREAD_DYING) {
current_thread->state = THREAD_FREE;
} else if(current_thread->sleeps_on != 0) {
current_thread->state = THREAD_SLEEPING;
} else {
if(scheduler_current_thread[this_cpu] != IDLE_THREAD_TID)
scheduler_add_to_ready_list(scheduler_current_thread[this_cpu]);
current_thread->state = THREAD_READY;
}
t = scheduler_ready_to_run.head;
/* Initialize the TID lowestDL to a thread with deadline larger than 0 */
/* if possible */
while (lowestDL == -1 && t != -1) {
if (thread_table[t].deadline > 0) {
lowestDL = t;
break;
}
t = thread_table[t].next;
}
t = scheduler_ready_to_run.head;
if (lowestDL != -1) {
/* If a deadline was found, find the lowest deadline */
while (t != -1) {
if (thread_table[t].deadline < thread_table[lowestDL].deadline &&
thread_table[t].deadline > 0) {
lowestDL = t;
}
t = thread_table[t].next;
}
/* Set the thread with this deadline to the head */
if (lowestDL == scheduler_ready_to_run.tail &&
lowestDL != scheduler_ready_to_run.head) {
scheduler_ready_to_run.tail = thread_table[lowestDL].previous;
thread_table[scheduler_ready_to_run.tail].next = -1;
thread_table[lowestDL].next = scheduler_ready_to_run.head;
thread_table[scheduler_ready_to_run.head].previous = lowestDL;
thread_table[lowestDL].previous = -1;
scheduler_ready_to_run.head = lowestDL;
}
else if (lowestDL != scheduler_ready_to_run.head) {
thread_table[thread_table[lowestDL].previous].next = thread_table[lowestDL].next;
thread_table[thread_table[lowestDL].next].previous = thread_table[lowestDL].previous;
thread_table[lowestDL].next = scheduler_ready_to_run.head;
thread_table[scheduler_ready_to_run.head].previous = lowestDL;
thread_table[lowestDL].previous = -1;
scheduler_ready_to_run.head = lowestDL;
}
}
/* Remove the head and run it */
t = scheduler_remove_first_ready();
thread_table[t].state = THREAD_RUNNING;
spinlock_release(&thread_table_slock);
scheduler_current_thread[this_cpu] = t;
/* Schedule timer interrupt to occur after thread timeslice is spent */
timer_set_ticks(_get_rand(CONFIG_SCHEDULER_TIMESLICE) +
CONFIG_SCHEDULER_TIMESLICE / 2);
}
