using System;
using System.Collections.Concurrent;
using System.Threading;

class Driver
{
	static DateTime targetTime;
	static bool finished() {
		DateTime now = DateTime.UtcNow;
		return now > targetTime;
	}

	public static void Main ()
	{
		int gcCount = 0;
		int joinCount = 0;
		targetTime = DateTime.UtcNow.AddSeconds(30);

		Thread gcThread = new Thread (() => {
			while (!finished()) {
				GC.Collect ();
				gcCount++;
				Thread.Sleep (1);
			}
		});

		gcThread.Start ();

		// Create threads then join them for 30 seconds nonstop while GCs occur once per ms
		while (!finished()) {
			BlockingCollection<Thread> threads = new BlockingCollection<Thread> (new ConcurrentQueue<Thread> (), 128);

			Thread joinThread = new Thread (() => {
				for (int i = 0; ; ++i) {
					Thread t = threads.Take ();
					if (t == null)
						break;
					t.Join ();

					// Uncomment this and run with MONO_LOG_LEVEL=info MONO_LOG_MASK=gc
					// to see GC/join balance in real time
					//Console.Write ("*");
				}
			});
			joinThread.Start ();
			
			const int makeThreads = 10*1000;
			for (int i = 0; i < makeThreads; ++i) {
				Thread t = new Thread (() => { Thread.Yield (); });
				t.Start ();

				threads.Add (t);
			}

			threads.Add (null);
			joinThread.Join ();

			joinCount += makeThreads;
			Console.WriteLine("Performed {0} GCs, created {1} threads. Finished? {2}", gcCount, joinCount, finished());
		}
		gcThread.Join ();
	}
}