Tracking down semaphore problems


1) Give a description of the problem
I’ve been noticing a number of ‘waited at semaphore’ messages in the logs for some of my pistons. These semaphores have been popping up, even in very basic Pistons. I don’t think I have too busy of a home automation network, so unsure why these are occurring. I have a couple of smart plugs, but notice that they spam the IDE with power change messages - not sure if that’s something that should be looked at?

I’m curious if semaphore waits are specific to webcore, or if this is something I can track down these in the smartthings IDE?


Still hoping to get a little input on this. Thanks!


If you have multiple triggers (orange lightning bolts) in a single piston then chances are you’d semaphore messages. Post a sample green snapshot of a piston.


Loops and While Loops are also culprits…

Monitoring power changes can also spam your home network.


So are semaphores specific to webcore or is that something that shows up in Live Logging in the ST page?

I only have a couple of Loops and While Loops and I unplugged my smart outlets because I noticed they were blasting my home network with so many updates (is there anything I can do about that?). If a ‘while loop’ is running and another piston tries to execute - is it going to always cause a semaphore?

Is there a way to start identifying the root cause of the semaphore; I would really like to clean things up and get them working more smoothly.