How to debug the Flink garbage collection application?

Question

I am using Flink 1.1.4 and added configuration options for debugging memory to flink-conf.yaml , as indicated in Debugging memory and performance :

 taskmanager.debug.memory.startLogThread: true taskmanager.debug.memory.logIntervalMs: 1000 

After restarting Flink, I see new options added to the task manager interface, but I do not see new logs.

Any idea on what I might be missing?