+#include <string.h>
+#include <stdlib.h>
+
#include "threads.h"
#include "schedule.h"
#include "common.h"
/** Constructor */
Scheduler::Scheduler() :
+ is_enabled(NULL),
+ enabled_len(0),
+ curr_thread_index(0),
current(NULL)
{
}
+void Scheduler::set_enabled(Thread *t, bool enabled_status) {
+ int threadid=id_to_int(t->get_id());
+ if (threadid>=enabled_len) {
+ bool * new_enabled=(bool *)malloc(sizeof(bool)*(threadid+1));
+ memset(&new_enabled[enabled_len], 0, (threadid+1-enabled_len)*sizeof(bool));
+ if (is_enabled != NULL) {
+ memcpy(new_enabled, is_enabled, enabled_len*sizeof(bool));
+ free(is_enabled);
+ }
+ is_enabled=new_enabled;
+ enabled_len=threadid+1;
+ }
+ is_enabled[threadid]=enabled_status;
+}
+
/**
* Add a Thread to the scheduler's ready list.
* @param t The Thread to add
void Scheduler::add_thread(Thread *t)
{
DEBUG("thread %d\n", t->get_id());
- readyList.push_back(t);
+ set_enabled(t, true);
}
/**
{
if (current == t)
current = NULL;
- else
- readyList.remove(t);
+ set_enabled(t, false);
}
/**
- * Force one Thread to wait on another Thread. The "join" Thread should
- * eventually wake up the waiting Thread via Scheduler::wake.
- * @param wait The Thread that should wait
- * @param join The Thread on which we are waiting.
+ * Prevent a Thread from being scheduled. The sleeping Thread should be
+ * re-awoken via Scheduler::wake.
+ * @param thread The Thread that should sleep
*/
-void Scheduler::wait(Thread *wait, Thread *join)
+void Scheduler::sleep(Thread *t)
{
- ASSERT(!join->is_complete());
- remove_thread(wait);
- join->push_wait_list(wait);
- wait->set_state(THREAD_BLOCKED);
+ set_enabled(t, false);
+ t->set_state(THREAD_BLOCKED);
}
/**
*/
void Scheduler::wake(Thread *t)
{
- add_thread(t);
+ set_enabled(t, true);
t->set_state(THREAD_READY);
}
/**
- * Remove one Thread from the scheduler. This implementation defaults to FIFO,
- * if a thread is not already provided.
+ * Select a Thread. This implementation defaults to round-robin, if a
+ * thread is not already provided.
*
* @param t Thread to run, if chosen by an external entity (e.g.,
* ModelChecker). May be NULL to indicate no external choice.
*/
Thread * Scheduler::next_thread(Thread *t)
{
- if (t != NULL) {
- current = t;
- readyList.remove(t);
- } else if (readyList.empty()) {
- t = NULL;
+ if ( t == NULL ) {
+ int old_curr_thread = curr_thread_index;
+ while(true) {
+ curr_thread_index = (curr_thread_index+1) % enabled_len;
+ if (is_enabled[curr_thread_index]) {
+ t = model->get_thread(int_to_id(curr_thread_index));
+ break;
+ }
+ if (curr_thread_index == old_curr_thread) {
+ print();
+ return NULL;
+ }
+ }
} else {
- t = readyList.front();
- current = t;
- readyList.pop_front();
+ curr_thread_index = id_to_int(t->get_id());
}
+ current = t;
print();
-
return t;
}
DEBUG("Current thread: %d\n", current->get_id());
else
DEBUG("No current thread\n");
- DEBUG("Num. threads in ready list: %zu\n", readyList.size());
-
- std::list<Thread *, MyAlloc< Thread * > >::const_iterator it;
- for (it = readyList.begin(); it != readyList.end(); it++)
- DEBUG("In ready list: thread %d\n", (*it)->get_id());
}