Support Advisory 52805: Instrumentation decisions can trigger high CPU within the AppDynamics.Agent.Coordinator Windows Service
This document describes the support advisory for an AppDynamics product.
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>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.