Lazy Chunk Load

Vanilla chunk loading schedules a large number of chunks around a player at once, which can overload the server CPU and collapse the tick rate. Lazy Chunk Load paces that work instead, and it does not make chunk loading faster; it makes the process steadier. The rate is adjusted from the current CPU usage, so the server runs at full speed when load is low and slows when usage spikes.

When a player stands still, the mod uses idle CPU time to preload ungenerated chunks around them, starting with the chunks under the feet and in line of sight. It pauses during world saves to avoid stalling them, and it lifts its limits immediately when a player steps onto an unloaded chunk. Login warmup limits loading for the first ten seconds after joining so the initial terrain arrives quickly. Status lines are written to logs/latest.log every five seconds.

The mod is server-side only, so clients need nothing and players join without installing it. It works on singleplayer too, and it is published for Fabric, Forge and NeoForge. Files exist for 1.20.1, 1.21.1 – 1.21.11, and 26.1 – 26.2, with 1.3.0 as the latest build on each loader. The code is released under the MIT License and is not open source. Enabled by default, the mod needs no configuration in most cases.