Strange loop time overrun messages

Technical Programming
1

I’ve been puzzling why our C++ robot occasionally reports a loop time overrun along with information that is manifestly nonsense. For example:

Watchdog not fed within 0.010000s
Loop time of 0.010000s overrun

Default RobotPeriodic() method... Override me!
    LiveWindow::UpdateValues(): 0.022000s
    RobotPeriodic(): 0.128000s
    SmartDashboard::UpdateValues(): 0.713000s
    DisabledPeriodic(): 16.507000s
    DisabledInit(): 7.383000s
    Shuffleboard::Update(): 0.971000s

Notice the time for DisabledPeriodic is over 16 seconds. That’s clearly NOT what’s happening from the behavior of the robot!

The problem appears to be in the Watchdog::PrintEpochs method where epoch.getValue().count() is divided by 1.0e6 but epoch values are in nanoseconds according to the Watchdog.h file.

I took a quick look at the Java version, but it is unclear to me whether the same problem exists there.

If you’re seeing these messages reporting time intervals in seconds, just treat them as milliseconds and they will make sense.

(Reported on github as allwpilib issue #2392.)

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