Exception Overhead - Part 2

Yesterday I looked at the overhead associated with throwing an exception. Driving into work today, I wondering, “what’s the cost involved in creating the exception object?”

So I added this method:

public sealed class Methods
{
  public void DoGood()
  {
  }
    
  public void DoBad()
  {
    throw new NotImplementedException();
  }

  public void DoSomething()
  {
    var exception = new NotImplementedException();
  }
}

And added it to the timings:

private static void TimeExceptions()
{
  const int iterations = 500000;

  var methods = new Methods();
    
  Console.Out.WriteLine("Bad Action: " + new Action(() =>
  {
    for(var i = 0; i < iterations; i++)
    {
      try
      {
        methods.DoBad();
      }
      catch(NotImplementedException)
      {
      }
    }
  }).Time());

  Console.Out.WriteLine("Good Action: " + new Action(() =>
  {
    for(var i = 0; i < iterations; i++)
    {
      methods.DoGood();
    }
  }).Time());

  Console.Out.WriteLine("Some Action: " + new Action(() =>
  {
    for(var i = 0; i < iterations; i++)
    {
      methods.DoSomething();
    }
  }).Time());
}

Here are the results:

Bad Action: 00:00:21.3727088
Good Action: 00:00:00.0005447
Some Action: 00:00:04.9421599

Creating the object itself takes time. But throwing the exception adds a lot on top of that.

Somebody was wondering if I compared the time between two methods where one calls a stored proc that does nothing, and the other calls a stored proc that throws an exception. I may look into that.

Published: 04.02.2009 09:26:08 AM CST

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Jason Bock

Exception Overhead - Part 2