public class Mptest {
	static int runCount_now = 0;
	static int tasksLeft = 0;

	public static void main(String[] args) {
	
		int cpu = Runtime.getRuntime().availableProcessors();
		System.out.println("Cpu count: " + cpu);
		tasksLeft = 3*cpu;
		System.out.println("Task count: " + tasksLeft);
		
		for (int i = 1; i <= tasksLeft; i++) {
			cpuTest(i);
			tasksLeft = 3*cpu;
		}
	}
	
	static public void cpuTest(int threadCount)
	{
		long start = System.currentTimeMillis();
		final Object object = new Object();
		
		for (int i = 0; i < threadCount; i++) {
			Runnable runnable = new Runnable() {
				
				public void run() {
					boolean go_on = true;
					while(go_on)
					{
						spendTime();
						synchronized (object) {
							if(tasksLeft > 0)
								tasksLeft--;
							else
							{
								go_on = false;
								runCount_now--;
							}
							object.notify();
						}
					}

				}
			};
			Thread thread = new Thread(runnable);
			synchronized (object) {
				runCount_now++;
			}
			thread.start();
		}

		try {
			synchronized (object) {
				while(runCount_now > 0 || tasksLeft > 0)
				{
					//System.out.println("runCount_now: " + runCount_now);
					//System.out.println("tasksLeft: " + tasksLeft);
					object.wait();
				}
			}
		} catch (InterruptedException e) {
			e.printStackTrace();
		}
		long end = System.currentTimeMillis();
		System.out.println("Time with " + threadCount + " threads : " + (end - start));
	}
	
	static public int spendTime()
	{
		int runCount = 20000;
		int sum = 0;
		for (int i = 0; i < runCount; i++)
			for (int j = 0; j < runCount; j++)
				sum += j - i;
		//System.out.println("sum: " + sum);
		return sum;
	}
}