observer_cli
Visualize Erlang/Elixir Nodes On The Command Line
... in and out of the node, number of garbage collector runs, words of memory that were garbage collected, and the global reductions count for the node. Total scheduler utilization will equal 1.0 when all schedulers have been active all the time between the two refresh intervals. The result being that there is a decent chunk of CPU usage that would be mostly free for scheduling actual Erlang work (assuming the schedulers are busy waiting more than trying to select tasks to run).