Frequent Packet Loss Spikes - HHS-Team670/MustangLib GitHub Wiki

Frequent Packet Loss Spikes

Authors: Armaan, Aditi, Justin

Date: 7/8/23

Status: FIXED

Symptoms

  • Robot does not respond to commands or controller inputs
  • Drivebase appears to ignore (or delay) driver input

Diagnosis

  1. Check the log files for packet loss (it shows up as an orange bar on the graph)

    • Occasional spikes are OK. Bad packet loss hovers around 30-50% (or higher!) at all times.

  2. Check the log files for any loop over run errors.

  3. Find any subsystems that are running much longer than they should be

  4. Look at the mustangPeriodic() of an offending subsystem (See 2023 LEDs under Permanent Solutions)

Solutions

Temporary Solutions

Solution 1: Kill FRC_NetCommDaemon:

  1. Open a terminal or command line and SSH into the robot with ssh [email protected]

  2. Run pkill -9 FRC_NetCommDaemon

Solution 2: No Wi-fi Around Robot

  1. Minimize other Wi-Fi connections near the robot, this may alleviate some of the symptoms. Turn all phones/computers in the room to Airplane Mode.

Solution 3: Power Cycle:

  1. Power cycling is the slowest and worst solution, but is easy to do and will temporarily fix the issue.

Permanent Solutions

2023 LEDs

During the 2023 build season we ran into packet loss issues. Later we found that the problem was that the LEDs were updating every periodic, and these redundant updates caused loop overruns and packet loss. By fixing this minimized packet loss. (It still popped up occasionally but it significantly easier to deal with. Look at the temporary solution above)

Resources