Concurrent Chunk Management Engine - Forge

Concurrent Chunk Management Engine (Forge)

An unofficial Forge port of C2ME by ishland / RelativityMC, for Minecraft 1.20.1 and 1.18.2.
Original mod: https://modrinth.com/mod/c2me-fabric

Minecraft generates, loads, saves, and lights chunks on a single thread. On a modern
multi-core CPU that means most of your cores sit idle while you stutter through fresh
terrain. C2ME makes that work parallel - it's the engine behind buttery-smooth
exploration and fast world pre-generation on Fabric, now ported from scratch to
classic Minecraft Forge.

This is a community port, not made or endorsed by the original C2ME team. All the
hard engine work is theirs; this project just carries it to Forge. Please report
Forge-specific issues here, not to upstream C2ME.

SUPPORT & BUG REPORTS

Join the Discord: https://discord.gg/s7BYs6Njj5

This is where I handle issues, and it's by far the fastest way to reach me. Crashes,
mod conflicts, questions about which version to run, or a pack that generates slower
than you expect - post it there and I'll take a look. Reports from real modpacks are
how most of the compatibility fixes in this mod were found in the first place.

Bring your latest.log (or the crash report) plus the pack name and version.

WHAT IT DOES

• Multi-threaded world generation -> terrain, biomes, features, and structures
generate across all your cores.
• Multi-threaded chunk I/O -> loading and saving no longer stall the game thread.
• Multi-threaded lighting.
• No-tick view distance -> see farther without ticking (and lagging) those chunks.
• Smarter scheduling and lower allocation overhead during worldgen.
• Worldgen thread-safety fixes for a pile of vanilla structure-generation bugs.

Ships as a single mod built from per-feature modules, each toggleable individually.

PERFORMANCE - MINECRAFT 1.20.1

C2ME spreads the chunk pipeline - worldgen, I/O, and lighting - across every CPU core
instead of one. The result is dramatically faster world generation and pre-generation.

Tested on four heavy 1.20.1 Forge packs (300-400 mods each), identical protocol:
/chunky radius 1000, 16,129 chunks per pack.

Across all four runs: 64,516 chunks generated. Zero crashes, zero corruption.

Give it RAM. C2ME keeps many chunks in flight at once, so it trades memory for speed.
Packs that choke at 8 GB run great with a little headroom. No code changes, just heap:

PERFORMANCE - MINECRAFT 1.18.2

The 1.18.2 build is not a plain backport. It carries the modernized threading engine
from the 1.20.1 line - newer than what upstream C2ME ever shipped for 1.18.2 - plus
two things that matter specifically on this version:

• Built-in Starlight light engine. On 1.18.2 the single-threaded light engine is
the pre-generation bottleneck, so this build integrates Starlight's rewritten
engine (Spottedleaf / PaperMC, LGPL-3.0 - license and full module source included).
It disables itself automatically if you already run standalone Starlight.
• Auto-tuned worldgen feed. No flags, no config, no commands - it measures your
hardware while generating and tunes itself as it goes.

Vanilla 1.18.2 vs C2ME, same server, same seed, /chunky radius 1000 (16,129 chunks):

Modpacks, client-side, on the settings the mod ships with - no flags, no config edits.
Each pack measured twice: once with C2ME removed, once with it installed.

Same story on RAM as 1.20.1 - give it headroom and it will use it:

A lot of the work on 1.18.2 went into packs that could not finish a pre-generation at
all. Thread-unsafe worldgen mods are detected at load and contained automatically -
one worldgen stage is serialized for the one mod that needs it, and everything else
keeps generating in parallel. No commands, no config, no opt-in.

REQUIREMENTS

• 1.20.1 -> Minecraft 1.20.1 • Forge 47.x • Java 17
• 1.18.2 -> Minecraft 1.18.2 • Forge 40.x • Java 17

Download the file that matches your Minecraft version - they are separate builds.

COMPATIBILITY

C2ME is built to sit alongside the usual Forge performance stack. Embeddium,
ModernFix, FerriteCore, ServerCore, Canary, and more. When it detects another mod
already optimizing the same code (Canary, Radium, and other Lithium forks), it steps
aside for just those overlapping pieces so nothing crashes, while its unique
multi-threaded generation keeps running on top. Known conflicts with mods like NBTac,
LongNbtKiller, and MoreMobVariants are handled the same way, no config needed.

If you already run Canary or ServerCore, C2ME's biggest addition is the threaded
world generation they don't provide.

On 1.18.2 the same idea covers thread-unsafe worldgen mods. Lost Cities, Blueprint,
Large Ore Deposits, Skyblock Builder and Ore Tweaker are recognised at load, and only
the stage each of them is unsafe in gets serialized. Hit one I don't know about yet?
Bring the log to Discord and it will be added.

CONFIGURATION

• Settings live in config/c2me.toml.
• Any module can be disabled with a JVM flag:
-Dc2me.disableModule.MODULE=true (e.g. -Dc2me.disableModule.opts.scheduling=true)
• There are no commands, and there never will be - it is plug and play.

KNOWN NOTES

• Needs adequate RAM -> see Performance.
• Because it replaces the chunk-storage backend, a few mods that reach directly into
vanilla chunk-storage internals may need per-mod tweaks. Please report any you hit
on Discord: https://discord.gg/s7BYs6Njj5

CREDITS & LICENSE

Original C2ME © 2021-2024 ishland and RelativityMC.
Source: https://github.com/RelativityMC/C2ME-fabric
Licensed under the MIT License; this port is redistributed under the same license,
with the full notice included in the jar. Huge thanks to the C2ME team - this port
exists only because of their work.

The 1.18.2 build additionally includes the Starlight light engine, © Spottedleaf and
the PaperMC project, licensed under LGPL-3.0. Its license is included in the jar, and
the complete corresponding source of that module is published here:
https://gitlab.com/thescriptersdk/starlight-c2me-source
Upstream Starlight: https://github.com/PaperMC/Starlight