internal void Start()
{
thread = Thread.CurrentThread;
CurrentTaskScheduler = this;
while (!stopRequested)
{
Task w = queuedTasks.Pop();
if (w == null)
{
TaskScheduler other = next;
while (other != this)
{
w = other.Steal();
if (w != null)
{
break;
}
other = other.next;
}
if (w == null)
{
if (!ThreadScheduler.StealDeque(this))
{
stopped = true;
CurrentTaskScheduler = null;
return;
}
else
{
continue;
}
}
}
// w should not be null at this point
w.RunTask();
} // end while(!stopRequested)
// we have been stopped
ThreadScheduler.AddTasks(queuedTasks);
stopped = true;
CurrentTaskScheduler = null;
}
internal static bool StealDeque(TaskScheduler tsStealer)
{
lock (dequeLock)
{
if (queuedTasks.Empty)
return false;
else
{
// swap deques
Deque<Task> tmp = tsStealer.QueuedTasks;
tsStealer.QueuedTasks = queuedTasks;
queuedTasks = tmp;
return true;
}
}
}
internal static void Start()
{
while (true)
{
int numThreads = 0;
int numBlockedThreads = 0;
int numStopRequested = 0;
bool anyQueuedTasks = false;
if (last != null)
{
// this is a little messy, but must work for 1 or more threads.
TaskScheduler cur = last.Next;
TaskScheduler prev = last;
bool done = false;
while (!done)
{
if (cur == last) // is this the last iteration?
done = true;
if (cur.IsStopped)
{
if (cur == prev) // there's only one thread
{
last = null;
break;
}
else
{
// remove cur, prev does not change
prev.Next = cur.Next;
if (cur == last) // we're removing the last thread
{
last = prev;
}
}
}
else
{
numThreads++;
if (cur.Thread != null && (cur.Thread.ThreadState & ThreadState.WaitSleepJoin) == ThreadState.WaitSleepJoin)
{
numBlockedThreads++;
}
if (!cur.QueuedTasks.Empty)
anyQueuedTasks = true;
if (cur.StopRequested)
{
numStopRequested++;
}
if (numThreads - numBlockedThreads - numStopRequested > numCores)
{
numStopRequested++;
cur.StopRequested = true;
}
prev = cur;
}
cur = cur.Next;
}
}
int numRunningThreads = numThreads - numBlockedThreads;
if (numCores > numRunningThreads)
{
if (!queuedTasks.Empty || anyQueuedTasks)
{
int numNewScheds = numCores - numRunningThreads;
for (int i = 0; i < numNewScheds; i++)
CreateTaskScheduler();
}
else if (numThreads == 0)
{
Monitor.Enter(dequeLock);
if (queuedTasks.Empty)
{
waiting = true;
Monitor.Wait(dequeLock);
Monitor.Exit(dequeLock);
}
else
{
Monitor.Exit(dequeLock);
for (int i = 0; i < numCores; i++)
CreateTaskScheduler();
}
}
}
Timer.SleepFor(sleepTime);
}
}
private static void CreateTaskScheduler()
{
TaskScheduler ts = new TaskScheduler();
if (last == null) // we have no TaskSchedulers
{
last = ts;
// we make it point to itself
ts.Next = ts;
}
else
{
ts.Next = last.Next;
last.Next = ts;
last = ts;
}
if (!queuedTasks.Empty)
StealDeque(ts);
JibuThreadPool.runTask(ts.Start);
}