Mono Sleep Performance Test

sleep_test.cs

using System;
using System.Threading;
using System.Diagnostics;
using System.Threading.Tasks;
using System.Reflection;

namespace TestSleep
{
	class MainClass
	{
		public static void Main (string[] args)
		{
			Console.WriteLine (GetMonoVersion ());
			Console.WriteLine ("Sleep performance test. Press enter to exit.");

			using(var performanceCounter = new PerformanceCounter ("Process", "% Processor Time", GetInstanceName(Process.GetCurrentProcess()), false))
			using(var ctSource = new CancellationTokenSource ())
			{
				var thread = new Thread (RunWithSleep) 
				{
					Name = "Dummy Sleep Thread"
				};
				thread.Start (ctSource.Token);

				var readLine = Task.Run (() => Console.ReadLine());
				while (!readLine.IsCompleted)
				{ 
					Console.Write("\rCPU Time: " + performanceCounter.NextValue() + "%");
					Thread.Sleep(TimeSpan.FromSeconds(1));
				}

				ctSource.Cancel ();
				thread.Join ();
			}
		}

		/**
		 * This Thread starts to sleep for one millisecond continously 
		 * and cause high CPU usage in Mono version >= 4.4.
		 */
		static void RunWithSleep(object cancellationToken)
		{
			Console.WriteLine ("Starting 'Dummy Sleep Thread'");
			var cancel = (CancellationToken)cancellationToken;
			while(!cancel.IsCancellationRequested)
			{
				Thread.Sleep(1);
			}

			Console.WriteLine ("'Dummy Sleep Thread' done");
		}

		static string GetInstanceName(Process process)
		{
			PerformanceCounterCategory processCategory = new PerformanceCounterCategory("Process");
			string[] instanceNames = processCategory.GetInstanceNames();
			foreach (string name in instanceNames)
			{
				if (name.StartsWith(process.Id.ToString()))
				{
					return name;
				}
			}

			throw new Exception ("Failed to find instance name");
		}

		static string GetMonoVersion()
		{
			Type type = Type.GetType("Mono.Runtime");
			if (type != null)
			{
				MethodInfo displayName = type.GetMethod("GetDisplayName", BindingFlags.NonPublic | BindingFlags.Static);
				if (displayName != null)
					return displayName.Invoke (null, null).ToString();
			}

			return "Unknown Version";
		}
	}
}