[Thad House]

Originally Posted by cjl2625

I've recently been a bit unhappy with my teleop main loop running kind of slow. Without any wait/sleep added in, I think each iteration takes around 50-70 ms, and sometimes starves Robot Drive (the "loop is not running fast enough" errors).

This year I've also been using a ton of variables in network tables, one for basically every constant on the robot. So that means maybe 50 network tables calls for each iteration of teleop.

When trying to figure out why the loop is slow, I considered that maybe retrieving these values is kind of slow, if it has to deal with things over the network. Could this actually be the case, or is the loop slowness probably caused by something else?

NetworkTables should actually be fairly efficient in that use case. All of the data is cached, so reading 50 variables should not take long at all.

There are a few other things to look at however. There are some methods in the WPILib that take 0.2-0.5ms to run, so if you are calling multiples of those they add up quick. One of the biggest culprits of this are the Driver Station mode checks. Calling IsEnabled, IsTeleop, or any of those types of methods do take a lot of time, so if you are calling those in a loop there becomes a lot of lag. Joystick get methods other then axes or buttons also take long to perform. The last ones are CAN calls, which can take a while, especially reads from CAN Talons, which depending on the parameter can take over a millisecond.