The top lights describe the communications pattern at that moment, and display differently on different nodes.
Red indicates a node is receiving data, green indicates sending data, and yellow means it's swapping data.
The middle section displays a log-log histogram of messages sent and received as a function of message size.
It encourages you to write your code so you send fewer large messages rather than many small messages,
an excellent way to optimize your parallel code.
The lower dials indicate estimates of the amount of the time spent communicating and the current bandwidth performance.
The colored needles show the momentary measurements and the black needles show the average measurement over
the run time of the code.