Multiple Thread with dependencies

 

Original Articles comes from http://msdn.microsoft.com/en-us/magazine/dd569760.aspx

However, I met problems. threads in parallel enters into dead lock.  My implement is a littile different with this article. I am using while to check threads. But if doing this, this thread will always hold the lock. Any idea? 

         while (_operations.Count != 0)
            {
                lock (_stateLock)
                {
                    using (_doneEvent = new ManualResetEvent(false))
                    {
                        {
                            foreach (var op in _operations.Values)
                            {
                                if (op.NumRemainingDependencies == 0)
                                {
                                    ThreadPool.UnsafeQueueUserWorkItem(state =>
                                            ProcessOperation((OperationData)state), op);
                                    _remainingCount++;
                                }
                            }
                            Console.WriteLine("First round!!");
                            _doneEvent.WaitOne();
                        }
                    }
                }

check thread satus, and found it is blocked by execute funciton.

Incorrect argument: | 
0:006> !SyncBlk 
Index         SyncBlock MonitorHeld Recursion Owning Thread Info          SyncBlock Owner
    3 000000000092f278            7         1 00000000000e8f70  16f8   0   0000000002884100 System.Object
-----------------------------

Check the code, no doubt that the lock is always held by the execute funciton, thread 6.

It doesn't has chance to release lock before it is waiting the statelock