Chunker

# Chunker - Official Support & Downloads Join our **Discord Community** for help, support, issues, feedback, and discussions. Click here to join: **(https://discord.gg/FUx7fk4PsA)** ## Contributions **PRs welcome** This repository is public. Fork the repo, create a branch, and open a pull request. I will merge changes that work and do not introduce issues. If I need changes I will leave feedback. Quick checklist: - Link the related issue if any. - Add a short description and steps to test. - Build must pass with `mvn clean package` using Java 25. ## Supported MC Versions - Target version: `26.1.2` - Requires Java 25 - Older Java 21 / pre-26.1.2 server builds are no longer supported by 26.1.2 and newer ## Supported Servers - Paper - Folia - Paper-compatible forks such as Pufferfish, Purpur, and Leaf Chunker still has fallback logic for non-Paper server paths, but the current plugin baseline is built for the `26.1.2` API and Java 25. <div style="display: flex; justify-content: space-between; width: 100% !important;"> <img src="https://www.davids-repo.dev/mc/chunker1.png" style="width: 49% !important; height: auto;"> <img src="https://www.davids-repo.dev/mc/chunker2.png" style="width: 49% !important; height: auto;"> </div> ## Overview Chunker is designed to be more efficient and resilient than traditional pre-generators. Many pre-generators track thousands of chunks in memory, risking significant rollback or data loss if the server crashes. Chunker, by contrast, only tracks minimal state like the current iterator position, submitted progress, completed progress, and the generation center, so crashes or restarts have less impact on the generation process. Chunker works best on Paper and Paper forks because it can use asynchronous chunk-loading through `CompletableFuture`. Folia uses its region scheduler path. On non-Paper server paths, Chunker falls back to synchronous loading behavior. You can configure Chunker to run automatically **only** when there are no players online and to halt if a player joins. This behavior is controlled by `auto_run` in `settings.yml`. You can also adjust how aggressively each dimension runs by changing `task_queue_timer` and `parallel_tasks_multiplier`. ## Optimized JVM Launch Parameters (`start.bat`) <details> <summary> View run.bat Source Code </summary> ```bat @echo off for %%f in (*.jar) do set JAR=%%f REM Launching Java with Aikar-style flags java ^ -Xms1G ^ -Xmx30G ^ -XX:+UseG1GC ^ -XX:+UnlockExperimentalVMOptions ^ -XX:G1NewSizePercent=30 ^ -XX:G1MaxNewSizePercent=40 ^ -XX:G1HeapRegionSize=8M ^ -XX:G1ReservePercent=20 ^ -XX:G1HeapWastePercent=5 ^ -XX:G1MixedGCCountTarget=4 ^ -XX:InitiatingHeapOccupancyPercent=15 ^ -XX:G1MixedGCLiveThresholdPercent=90 ^ -XX:G1RSetUpdatingPauseTimePercent=5 ^ -XX:SurvivorRatio=32 ^ -XX:+PerfDisableSharedMem ^ -XX:MaxTenuringThreshold=1 ^ -XX:+UseCompressedOops ^ -XX:+DisableExplicitGC ^ -XX:+AlwaysPreTouch ^ -XX:+ParallelRefProcEnabled ^ -XX:+UseNUMA ^ -XX:ParallelGCThreads=16 ^ -XX:ConcGCThreads=16 ^ -XX:MaxGCPauseMillis=50 ^ -Dusing.aikars.flags=https://mcflags.emc.gs ^ -Daikars.new.flags=true ^ -jar "%JAR%" --nogui pause ``` </details> - `Xms1G` and `Xmx30G` should be updated to match your server's minimum and maximum memory. - Update both `XX:ParallelGCThreads` and `XX:ConcGCThreads` to match your CPU thread count. --- ## Paper Config > **Note:** On non-Paper servers, Paper async chunk functionality will not be used. > On Paper-based servers, you can tune chunk generation and I/O parallelism for better pre-generation throughput. In your `paper-global.yml` or equivalent, consider increasing the parallelism for chunk generation and I/O: ```yaml chunk-loading-advanced: auto-config-send-distance: true player-max-concurrent-chunk-generates: -1 player-max-concurrent-chunk-loads: -1 chunk-loading-basic: player-max-chunk-generate-rate: -1.0 player-max-chunk-load-rate: -1.0 player-max-chunk-send-rate: -1.0 chunk-system: gen-parallelism: default io-threads: 16 worker-threads: 16 region-file-cache-size: 16 ``` - Adjust `io-threads` and `worker-threads` to match or approach your CPU's thread count. - By default, Paper may not use all available CPU threads for chunk work. - Lower `region-file-cache-size` if running pre-generation on a fresh world with no players online. ## Command Usage The primary commands are: ```text /pregen <ParallelTasksMultiplier> <PrintUpdateDelay> <dimension> <Radius or "default"> /pregenoff /pregen reset <dimension> ``` ### Examples 1. `/pregen 4 10s minecraft:overworld default` - Pre-generates the overworld. - Queues 4 chunk-loading tasks per scheduler cycle. - Prints progress logs every 10 seconds. - `default` uses the world border as the radius. 2. `/pregen 6 5s minecraft:overworld 1000b` - Pre-generates the overworld. - Queues 6 tasks per scheduler cycle. - Prints logs

# Chunker - Official Support & Downloads

Join our Discord Community for help, support, issues, feedback, and discussions. Click here to join: (https://discord.gg/FUx7fk4PsA)**

## Contributions

PRs welcome

This repository is public. Fork the repo, create a branch, and open a pull request. I will merge changes that work and do not introduce issues. If I need changes I will leave feedback.

Quick checklist: - Link the related issue if any. - Add a short description and steps to test. - Build must pass with `mvn clean package` using Java 25.

## Supported MC Versions

• Target version: `26. 1. 2`
• Requires Java 25
• Older Java 21 / pre-26. 1. 2 server builds are no longer supported by 26. 1. 2 and newer

## Supported Servers

• Paper
• Folia
• Paper-compatible forks such as Pufferfish, Purpur, and Leaf

Chunker still has fallback logic for non-Paper server paths, but the current plugin baseline is built for the `26. 1. 2` API and Java 25.

## Overview

Chunker is designed to be more efficient and resilient than traditional pre-generators. Many pre-generators track thousands of chunks in memory, risking significant rollback or data loss if the server crashes. Chunker, by contrast, only tracks minimal state like the current iterator position, submitted progress, completed progress, and the generation center, so crashes or restarts have less impact on the generation process.

Chunker works best on Paper and Paper forks because it can use asynchronous chunk-loading through `CompletableFuture`. Folia uses its region scheduler path. On non-Paper server paths, Chunker falls back to synchronous loading behavior.

You can configure Chunker to run automatically only* when there are no players online and to halt if a player joins. This behavior is controlled by `auto_run` in `settings.yml`. You can also adjust how aggressively each dimension runs by changing `task_queue_timer` and `parallel_tasks_multiplier`.

## Optimized JVM Launch Parameters (`start.bat`)

View run.bat Source Code

```bat @echo off for %%f in (.jar) do set JAR=%%f REM Launching Java with Aikar-style flags java ^ -Xms1G ^ -Xmx30G ^ -XX:+UseG1GC ^ -XX:+UnlockExperimentalVMOptions ^ -XX:G1NewSizePercent=30 ^ -XX:G1MaxNewSizePercent=40 ^ -XX:G1HeapRegionSize=8M ^ -XX:G1ReservePercent=20 ^ -XX:G1HeapWastePercent=5 ^ -XX:G1MixedGCCountTarget=4 ^ -XX:InitiatingHeapOccupancyPercent=15 ^ -XX:G1MixedGCLiveThresholdPercent=90 ^ -XX:G1RSetUpdatingPauseTimePercent=5 ^ -XX:SurvivorRatio=32 ^ -XX:+PerfDisableSharedMem ^ -XX:MaxTenuringThreshold=1 ^ -XX:+UseCompressedOops ^ -XX:+DisableExplicitGC ^ -XX:+AlwaysPreTouch ^ -XX:+ParallelRefProcEnabled ^ -XX:+UseNUMA ^ -XX:ParallelGCThreads=16 ^ -XX:ConcGCThreads=16 ^ -XX:MaxGCPauseMillis=50 ^ -Dusing.aikars.flags=https://mcflags.emc.gs ^ -Daikars.new.flags=true ^ -jar "%JAR%" --nogui pause ```

• `Xms1G` and `Xmx30G` should be updated to match your server's minimum and maximum memory.
• Update both `XX:ParallelGCThreads` and `XX:ConcGCThreads` to match your CPU thread count.
• --

## Paper Config

> Note: On non-Paper servers, Paper async chunk functionality will not be used. > On Paper-based servers, you can tune chunk generation and I/O parallelism for better pre-generation throughput.

In your `paper-global.yml` or equivalent, consider increasing the parallelism for chunk generation and I/O:

```yaml chunk-loading-advanced: auto-config-send-distance: true player-max-concurrent-chunk-generates: -1 player-max-concurrent-chunk-loads: -1

chunk-loading-basic: player-max-chunk-generate-rate: -1. 0 player-max-chunk-load-rate: -1. 0 player-max-chunk-send-rate: -1. 0

chunk-system: gen-parallelism: default io-threads: 16 worker-threads: 16

region-file-cache-size: 16 ```

• Adjust `io-threads` and `worker-threads` to match or approach your CPU's thread count.
• By default, Paper may not use all available CPU threads for chunk work.
• Lower `region-file-cache-size` if running pre-generation on a fresh world with no players online.

## Command Usage

The primary commands are:

```text /pregen /pregenoff /pregen reset ```

### Examples

1. `/pregen 4 10s minecraft:overworld default` - Pre-generates the overworld. - Queues 4 chunk-loading tasks per scheduler cycle. - Prints progress logs every 10 seconds. - `default` uses the world border as the radius.

2. `/pregen 6 5s minecraft:overworld 1000b` - Pre-generates the overworld. - Queues 6 tasks per scheduler cycle. - Prints logs