In the traces tab --> Slowest Method Calls and Count we show if you find Un-instrumented block of code the reason is as follows:
Basically, What is un-instrumented block of code in APM Insight?
By default, APM Insight agent monitors known frameworks and libraries in your application code. However, there may be certain methods which may not be instrumented by the agent. Such kind of code are classified as ' un-instrumented block of code'.
If you prefer to monitor these blocks of code, you can instrument them using custom instrumentation. Custom instrumentation allows you to monitor specific blocks of your application code.
Custom Instrumentation for Latest APM Insight .Net agent can be performed using the Custom Instrumentation Manager Tool which is bundled with the Agent itself
Working with Custom Instrumentation Manager Tool
1. From the Windows Start menu or Start screen (Windows 8/Windows Server 2012), launch the Custom Instrumentation Manager tool. Alternatively, it can be accessed by navigating to the installation directory of APM Insight C:\Program Files (x86)\ManageEngine\APM Insight .NET Agent\AgentApi --> DotNetAgent.Api.Manager
2. Load an application DLL from the bin directory of a web application. The below image shows loading a DLL.
3. Choose required methods / classes or even entire assemblies from left pane and add it to the right pane for monitoring. The number of methods selected will be shown at the bottom.
4. The component names can be set by editing the component text box individually.
5. Alternatively select a group of components, right click and select "Set Component Name" option to assign a component for multiple methods.
6. Click the Save button. After saving, the status bar will show a message "Recycle the application pools to take effect". Note that the message appears only when one or more w3wp processes are running.
7. The added methods will be displayed along with the text [custom].