Please add a config option that makes chunk pregeneration automatically start when the player count reaches 0 and stop whenever it goes above that. (For smaller servers.)

If you use the issue search feature you should find multiple posts where I've answered this already, but in short: I do not see a strong reason for this to be included in Chunky, and pre-generating with players online should have little impact on your performance, especially if there are only a few players online.

If you feel like you really need it you can use an existing addon plugin to achieve this functionality, such as ChunkyPause (which does the player pausing you are talking about), or write your own using the API to pause and manage tasks in any way you like.

If you need any help with any of the above please use our Support Discord and visit the chunky channel there. You should receive responses much more quickly than here on Github.

I saw you came by the Discord; wanted to respond there but saw you already left.

In regards to the performance impact you are seeing on Forge - this is probably almost entirely caused by the mods you have doing things to hang the main thread on world gen. If you can identify any that are causing these issues for you, I would heavily recommend reporting this behavior to the authors of those mods, as this can be considered a bug. World gen is not done on the main server thread, so any mods stalling it significantly during world gen is just not acceptable IMO.

With that said, glad you found the data pack for pausing! If you had mentioned you were on Forge, I would have linked to that instead of the plugin example.

Wish you happy pre-genning!

Just as a follow up for anyone who might come across this post in the future: Riku and I troubleshooted a bit on Discord and as it turns out, the issue was just memory allocation.

If you're experiencing crashes, before turning to alternatives, make sure your memory allocation for the server is set correctly, with a few gigabytes of overhead for the container / system.