What is the meaning of active threads under threads in investigator?
<Please see attached file for image>
The top level "Active Threads" metric indicate count of all the threads running in the JVM including system/JVM threads, agent threads and application threads.
Each sub node indicate the classname of implemented thread class.
Every node will also have active threads metric which indicate thread count of that particular class.
https://ca--c.na13.visual.force.com/apex/KBArticleUpdate?kbid=TEC601799&caseNumber=00755702