Is there some interface to get the board’s cpu usage and FPS data?
It is possible to get the board’s CPU usage and FPS. Depending on the platform you are using you may have to implement the services and natives to retrieve the CPU usage and FPS. Here is an example of CPU usage implementation on the STM32F7508-DK demo platform Platform-STMicroelectronics-STM32F7508-DK/cpuload.c at master · MicroEJ/Platform-STMicroelectronics-STM32F7508-DK · GitHub.
Here is the Simple Native Interface documentation if you want to be able to access this data from your Java code Simple Native Interface (SNI) — MicroEJ Documentation.
Hope this helps,