Below are two solutions to adddress this error:
1) Disable the thread dump feature for agents in which thread dumps are not needed. This can be achieved by setting the following properties in the in IntroscopeAgent.profile:
2) Increase introscope.enterprisemanager.threaddump.perftune.cache property with appropriate value(upperbound 40) in IntroscopeEnterpriseManager.properties file of EM. An EM restart is required after making changes to this properties.
Note: The increase in this value would affect the performance of Introscope Enterprise Manager.