we setup jenkins master and several agents. one of agents periodically deadlocked and cpu spiked. I found It because SynchronousCommandTransport$ReaderThread.run from remoting.jar. (ref: https://wiki.jenkins.io/display/JENKINS/Remoting+issue)
I added some screenshots. I really appreciate if you take a look and help us to find root cause.
agent server stats:
tracking PID 15699: ( It was remoting.jar )