Measure request time on server

Question

Hi,

I would like to compute time that spans between two particular moments:

- start moment would be call to method IDispatchMessageInspector
.AfterReceiveRequest
- end moment would be call to method IDispatchMessageInspector.BeforeSendReply

In fact, I would like to compute time that is needed to execute service call user code. I thought that those two methods of IDispatchMessageInspector are good place to hook. But unfortunately I don't know how to associate AfterReceiveRequest for message with corresponding BeforeSendReply call.

Thanks Pawel.

Answer 1

Here's a parameter inspector I once wrote to measure performance of my WCF service methods. Notice that a Stopwatch is started and returned in the BeforeCall method which allows you to retrieve it in the AfterCall method as the correlationState parameter:

public class PerformanceCountersInspector : IParameterInspector
{
    public object BeforeCall(string operationName, object[] inputs)
    {
        return Stopwatch.StartNew();
    }

    public void AfterCall(string operationName, object[] outputs, object returnValue, object correlationState)
    {
        var watch = (Stopwatch)correlationState;
        watch.Stop();
        var time = watch.ElapsedMilliseconds;
        // Do something with the result
    }
}

The difference here is that using a parameter inspector will not take into account the time taken to serialize input/output parameters. It will only account for the operation time. If you want to include serialization time you might use IDispatchMessageInspector. The BeforeSendReply method also has a correlationState that works the same.

---

UPDATE:

You could configure the parameter inspector in web.config by writing a behavior extension:

public class PerformanceCountersBehaviorExtension : BehaviorExtensionElement, IServiceBehavior
{
    public override Type BehaviorType
    {
        get { return typeof(PerformanceCountersBehaviorExtension); }
    }

    protected override object CreateBehavior()
    {
        return this;
    }

    void IServiceBehavior.AddBindingParameters(ServiceDescription serviceDescription, ServiceHostBase serviceHostBase, Collection<ServiceEndpoint> endpoints, BindingParameterCollection bindingParameters)
    {
    }

    void IServiceBehavior.ApplyDispatchBehavior(ServiceDescription serviceDescription, ServiceHostBase serviceHostBase)
    {
        foreach (ChannelDispatcher channelDispatcher in serviceHostBase.ChannelDispatchers)
        {
            foreach (var endpoint in channelDispatcher.Endpoints)
            {
                foreach (var operation in endpoint.DispatchRuntime.Operations)
                {
                    var inspector = new PerformanceCountersInspector();
                    operation.ParameterInspectors.Add(inspector);
                }
            }
        }
    }

    void IServiceBehavior.Validate(ServiceDescription serviceDescription, ServiceHostBase serviceHostBase)
    {
    }
}

And in your configuration file you register the extension:

<services>
  <service name="MyAssembly.MyService" behaviorConfiguration="returnFaults">
    <endpoint address="" binding="basicHttpBinding" contract="MyAssembly.IMyServiceContract"/>
    <endpoint address="mex" binding="mexHttpBinding" contract="IMetadataExchange"/>
  </service>
</services>
<behaviors>
  <serviceBehaviors>
    <behavior name="returnFaults">
      <serviceDebug includeExceptionDetailInFaults="true"/>
      <serviceMetadata httpGetEnabled="true"/>
      <perfCounters />
    </behavior>
  </serviceBehaviors>
</behaviors>
<extensions>
  <behaviorExtensions>
    <add name="perfCounters" type="MyAssembly.PerformanceCountersBehaviorExtension, MyAssembly, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null" />
  </behaviorExtensions>
</extensions>

Answer 2

What about this?

public object AfterReceiveRequest(
    ref System.ServiceModel.Channels.Message request, 
    IClientChannel channel, InstanceContext instanceContext)
{
    return DateTime.Now;
}

public void BeforeSendReply(
    ref System.ServiceModel.Channels.Message reply, object correlationState)
{
    TimeSpan elapsed = DateTime.Now - ((DateTime)correlationState);
}

Answer 3

Bingo ! Thanks ! It is possible to attach that mechanizm to application from app.config file?