Chunk Steward

Requires CleanRoomMC https://cleanroommc.com/

Chunk Steward (initially uploaded as LazyChunks) is a 1.12.2 mod built to help with performance in world-gen heavy modpacks. This is built on Java 21 and requires Cleanroom to function. A normal Java 8 Forge install cannot run it.

It preloads chunks around the player when the server has spare time, and it throttles heavy chunk generation and world decoration during exploration so that TPS issues are minimized. The long stalls usually come from decoration, trees, ores, and structures, landing in one tick. This can be very important in server environments so that exploring players don't completely freeze up server ticks. Chunks near a player, and chunks for someone who just logged in, still come through. The result is somewhat slower chunk loading during exploration, but more stable TPS overall, with the chunks ahead of you filled in first.

Chunk Steward will also pregenerate a larger radius around a bed or respawn, and around places a player regularly occupies, in anticipation of further exploration. It does this when the server has spare time, to help prevent excessive server usage.

This also exposes an API that other mods can use to check server utilization and pace their own heavy work. Two mods that are using this now are Roguelike Dungeons - Arcana Edition and Arcana Quest Tweaks.