Execution time

• very fast
• bad resolution (10 milliseconds)

DateTime begin = DateTime.UtcNow;
...
DateTime end = DateTime.UtcNow;
Console.WriteLine("Execution time: " + (end-begin).TotalMilliseconds + " ms.");

• little bit slower
• can be unreliable on a PC with multiple processors or on processors with unconstant clock speed!

Stopwatch watch = new Stopwatch();
watch.Start();
...
watch.Stop();
Console.WriteLine("Execution time: " + watch.Elapsed.TotalMilliseconds + " ms.");

• measures only processors time kept by process
• if process is keeping multiple processors busy, the time of each processor will be added

TimeSpan begin = Process.GetCurrentProcess().TotalProcessorTime;
...
TimeSpan end = Process.GetCurrentProcess().TotalProcessorTime;
Console.WriteLine("Execution time: " + (end - begin).TotalMilliseconds + " ms.");

• http://kristofverbiest.blogspot.com/2008/10/beware-of-stopwatch.html