Shuffleboard and OpenJDK binary

When using Shuffleboard, the OpenJDK binary consumes a lot of cpu. After starting the DS and having the Shuffleboard loaded, the cpu consumption is high, but things seem to function acceptably.

However, if we close the lid on the DS laptop and then later open it back up, the cpu consumption of OpenJDK binary is even higher to the point the DS PC is unusable. This does not happen with every close and open of the lid but most of the time. When this occurs, we have to kill the shuffleboard and reload and it works until next lid close.

This is familiar. A couple years back our laptops really struggled with Shuffleboard. And resetting DS, at least between matches is good practice. Maybe just get in habit of closing it before sleeping the computer.

The problem with that solution is that the laptop is closed on the way to a match and then opened at the field. It may be closed again when leaving the staging area for the team position at the field wall and then opened again. We don’t want the laptop open when moving our driver station. We don’t want to be closing/restarting the DS code when on the field either. Note that this problem surfaced for us after the cancellation of 2020 season, so we have not been to a competition with this problem in play, but it concerns me.

What version of shuffleboard are you using?

Shuffleboard has been hogging resources for us too. Definitely seems to be worse when we have lots of graphs going.

Yep. It used to be a lot worse too. We switched the plotting backend for 2021: Change GraphWidget to ChartFX (#657) · wpilibsuite/shuffleboard@824258e · GitHub

My general recommendation is to use Glass if you want plots.

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I will have to check that when I am next in the lab, but its the at least the version released at start of 2021. Note we dont graph or do anything spectacular, pretty vanilla use of SB.

Shuffleboard is one of the “highest resouce” demanding thing we distribute (beaten only be wpimath). Also, sleep mode is wonky in all sorts of applications, it’s not a highly tested scenario. I wish I could say this bug will get looked into, but shuffleboard is minimally maintained at this point in time.

Is that because we are getting another new dashboard (glass) technology in 2022?

Partially. It’s more to due with there is no active developer for it. WPILib is a community/volunteer driven project. As such, volunteers come and go.