Hello! I have been running a server for a couple friends and I that includes, among other mods, Fluidic Power.

Lately we have been experiencing game stuttering while playing and lengthy "catching up" times when connecting to the server. I'm creating a post here because I have tried everything I can think of to troubleshoot, and have looked for solutions online to no avail.

I have isolated the cause to Fluidic Power after troubleshooting for some time:
- Neither server or client are using their maximum resources (CPU cores, memory, disk, network, etc.)
- Tested on both WiFi, Ethernet, and on WAN/LAN connections and confirmed the server has sufficient/reliable UDP bandwidth using iPerf3
- Disabling all mods alleviates the issue, while removing all mods except Fluidic Power causes the issue to return

Running the save locally with FluidicPower (and all other mods) enabled also does not have this stuttering problem.

If it's any help, the debug screen shows a high frame cycle and wait for update time, with a maximum value of 240.686 and 239.008 respectively after experiencing an instance of stuttering. Related updates show maximum values of 0.054 (Fluid Manager) and 12.557 (Electric Network).

Is this user error you think? Could we have too many electric poles and/or ones that are improperly placed? Our base isn't terribly big, we have yet to research the rocket.

Thank you for taking the time to read my post! I can share more information if needed, just let me know :)

Hello!

It sounds like there is two seperate things you are experiencing. The general slow down which causes length caching-up times. And the stuttering.

General Slow Down

The general slow down is a little hard to work around, because as you probably know Factorio is not optimized currently for mods like Fluidic Power. The main culprit is simply the amount of poles in your game, regardless of how they are placed. And you correctly saw this with the Electric Network time being quite high.

To work around this you could try to remove poles that's not needed. For example if you're doing city-blocks and have many unused blocks, then maybe delete the poles in those blocks until you need them. Or old parts of the factory that's no longer used. The best is to build new builds with substations because you don't need much of them.

If your friends are struggling to catch up then I would also suggesting pausing your game while they catch up. This will make it much easier. I think you can do it through the main menu. Their PCs basically has to run the entire game simulation faster than yours to catch up more information.

I explained more about the current engine limitations here if you're interested, and I've heard that it will actually much better in Factorio 2.0 :D

Stuttering

high frame cycle and wait for update time, with a maximum value of 240.686 and 239.008 respectively

Not really sure about this one. A quick google found me this post with a dev reply: "In multiplayer, the game will run multiple updates between rendering, if it starts falling behind the server." So it sounds like one of the PCs is slower than the rest, meaning it's struggling to keep up. In that case you're unfortunately reaching the limit of your game (unless you remove some poles), because it can only run as fast as the slowest PC playing on it. So what I would do is try to slow the game down to like 80% or 90% speed. You can do this using a console command.

I hope this helps. If you're still struggling feel free to continue asking questions :)

Thank you so much for your quick and detailed response!

It's good to know that it's not how they're placed but rather just too many placed that's the issue. I'll also definitely be using the pause function to help with catching up.

But yeah the stuttering thing is bizarre to me. It's one thing if the server just couldn't keep up and had to run slower, but the stuttering is what is making it nearly impossible to play (this is alleviated somewhat by reducing game speed as you described).
What is the strangest to me is that this happens when I connect to the server directly over LAN, and my client PC has sufficiently more power than the server PC itself. This is what led me to believe it was a UDP packet loss issue, but that didn't end up being the cause either.

That being said, I think that you have provided excellent solutions. I will assemble the team to start optimizing our layout, and will try running the game at a slower speed to compensate our clients.

Thank you again for your help and thank you SO MUCH for making this mod! It has been a dream of ours to manage realistic power distribution and it's incredibly satisfying when things go right (or wrong!). Happy Friday, cheers.