title: Multithreaded Singleton WCF Service
body: <p>In his book "Programming WCF Services", Juval Lowry expresses concerns about using Singleton Services because of the performance implications. </p>
  
  <p>In one of my projects I'm using a stateless singleton WCF Service declared like this:</p>
  
  <pre><code>[ServiceBehavior(InstanceContextMode = InstanceContextMode.Single,
     ConcurrencyMode = ConcurrencyMode.Multiple)]
  public class FooService : IFoo
  {
  }
  </code></pre>
  
  <p>The service is accessed from multiple Silverlight clients over httpsTransport. I've opted for a singleton because I see no need to burden the system the GC overhead when it is not really needed. Am I missing something or shouldn't this be the most efficient way to implement a stateless service that's equally fast if not faster than a PerCall instantiated service?</p>