Summary

AppDynamics has discovered that in certain cases, the process of making instrumentation decisions (on which methods to instrument) can trigger high CPU within the AppDynamics.Agent.Coordinator Windows Service.

Affected Software

This issue affects 4.1.x versions of the .NET agent previous to 4.1.6.1. 

Impact

High CPU overhead: The AppDynamics.Agent.Coordinator Windows service consumes high CPU while new applications are starting up. This can be problematic when instrumenting many IIS application pools which are continuously stopping and starting.

Workaround

You can apply the following workaround to address this issue immediately. This change moves instrumentation decisions from the Windows service to the instrumented process and will have no impact on visibility within AppDynamics.

Add the setting below under the <app-agents> element in config.xml on impacted servers:

<profiler>
   <legacy-instrumentation-decisions enabled="false" />
</profiler>
CODE

Note: This configuration is not included out-of-the-box because it could cause additional overhead for applications that continuously create and then tear down AppDomains many times throughout the life of the process.