Async - Minecraft Entity Multi-Threading Mod ⚙️

Async improves entity performance by processing entities in parallel across multiple CPU cores and threads.

Important❗

Async is currently in alpha testing and is experimental. Its use may lead to incorrect entity behavior and crashes.

What is Async? 🤔

Async enhances the performance of entity processing. The mod leverages multithreading, which allows multiple CPU cores to improve performance when handling a large number of entities.

💡 Key Benefits:

• ⚡ Improved TPS: Maintains stable tick times even with a large number of entities.
• 🚀 Multithreading: Utilizes multiple CPU cores for parallel entity processing.
• 🎲 Async Random Ticks (Experimental): Processes random ticks asynchronously for better performance.

📋 Requirements

• Minecraft: 26.1 or newer
• Java: 25 or newer
• Loader: Fabric, Quilt or NeoForge
• Dependency: Fabric API (on Fabric/Quilt)

📊 Performance Comparison (9000 Villagers)

Configuration	TPS	MSPT
Lithium + Async	20	41.8
Lithium (without Async)	4.4	225.4
Purpur	5.72	176.18

🛠️ Test Configuration

• Processor: AMD Ryzen 9 7950X3D
• RAM: 64 GB (16 GB allocated to the server)
• Minecraft Version: 1.21.4
• Number of Entities: 9000
• Entity Type: Villagers

Mod List Concurrent Chunk Management Engine, Fabric API, FerriteCore, Lithium, ScalableLux, ServerCore, StackDeobfuscator, TT20 (TPS Fixer), Tectonic, Very Many Players, Fabric Carpet.

⚠️ Incompatible Mods

• ❌ Moonrise - Known incompatibility
• ❌ Open Parties and Claims - Known incompatibility
• ⚠️ ...and there may be conflicts with other mods.

If you encounter issues with other mods, please report them on our GitHub or Discord.

🔧 Commands

Configuration

• /async config toggle — Enables or disables the mod in-game (no server restart required). Use this command to instantly see how Async improves your server.
• /async config reload — Reloads the configuration from disk.
• /async config setAsyncEntitySpawn [true|false] — Enables or disables parallel mob spawn processing (disabled by default). Without an argument, shows the current value. Warning: Not compatible with Carpet mod lagFreeSpawning rule.
• /async config setAsyncRandomTicks [true|false] — Enables or disables async random ticks processing (experimental feature, disabled by default). Without an argument, shows the current value.
• /async config synchronizedEntities — Lists entities that are currently processed synchronously. Defaults to minecraft:tnt, minecraft:item and minecraft:experience_orb.
• /async config synchronizedEntities add <entity|namespace:*> — Adds an entity type, or every entity of a namespace, to synchronized processing.
• /async config synchronizedEntities remove <entity|namespace:*> — Removes an entity type, or every entity of a namespace, from synchronized processing.

Statistics

• /async stats — Displays mod status, async spawn and random tick states, the total entity count, and the number of threads in use.
• /async stats entity — Shows the number of entities per world, along with how many of them are processed asynchronously.
• /async stats entity <number> — Additionally shows the top <number> (1-100) entity types by count in descending order, each marked as async or sync. For example, /async stats entity 10 displays the top 10 most numerous entity types.
• /async stats entity <number> <ticks> — Records for <ticks> ticks, then displays the top <number> entity types with their average mspt usage.

⚙️ Configuration

Async can also be configured through its config file:

• disabled — Fully disables the mod.
• maxThreads — Number of threads to use. Defaults to -1 (auto)
• enableAsyncSpawn — Parallel mob spawn processing.
• enableAsyncRandomTicks — Async random ticks (experimental).
• synchronizedEntities — Entity types that must be ticked on the main thread.

📥 Download

The mod is available on Modrinth

🔄 Minecraft Version Support

Full support is provided only for the latest version of Minecraft. Support for older Minecraft snapshots is not planned.

📭 Feedback

Our tracker for feedback and bug reports is available on GitHub:

You can also chat with us on Discord:

🙌 Acknowledgements

This mod is based on code from MCMTFabric, which in turn was based on JMT-MCMT. Huge thanks to Grider and jediminer543 for their invaluable contributions!