I recently set up a new Raspberry Pi 3 with Node Red V1.1.3. The Raspberry Pi 3 uses Raspberry Pi OS lite 5.4.
I copied the node red flows from one working system to this new system. Everything worked except that I noticed a huge CPU usage jump. The new system uses much less memory and has less apps running than the working system. The working system uses Node Red V1.1.2.
I troubled shoot the problem and found that the Serialport node caused the problem. If I remove the serialport node, then the CPU usage quickly drops down to normal level (2-4% typically). If I add the serialport node back, the CPU usage jumps more than 100% and the board will heat up quickly.
There are only two major differences that I can think of:
- Raspberry Pi OS (the working system has Desktop, the new system does not). I doubt that this is the problem.
- The working system uses Node Red v1.1.2. The new system uses Node Red v1.1.3. I doubt that this is the problem either.
What could cause the problem? Thanks for your help.