Tessellate

Tessellate is a NeoForge/Fabric performance mod for Minecraft 1.21.1. It groups distant loaded areas into independent regions and lets them run on different CPU cores. If one region gets too expensive, Tessellate can slow it down without dragging the rest of the server with it.

This works best when players or forced-loaded areas are spread out. One dense base, mob farm, or machine cluster is still one region, so Tessellate cannot split that work across several cores. It also doesn't replace single-thread optimizers such as Lithium.

Requirements and installation

• Minecraft 1.21.1
• NeoForge 21.1.x
• Java 21
• No required optimization-mod dependencies

Drop the JAR into the server's mods folder. The client install is optional. Players who have it get the GPU-rendered region map and boundary overlay, while everyone else can still use the particle fallback.

Performance

For a concrete comparison, we benchmarked four forced-loaded regions 2,048 blocks apart with 1,200 persistent zombies in each region. Parallel ticking cut median MSPT by 61.2% and p95 MSPT by 62.5%.

Both modes ran on Minecraft 1.21.1, NeoForge 21.1.248, Java 21, and the same nine-mod setup. This test is deliberately built around several separate regions. It is not a promise of the same speedup everywhere. Hardware, region layout, entity count, and installed mods all matter.

How it works

Tessellate divides the loaded world into 4x4-chunk sections. Nearby entity-ticking sections join into a region before they run, which keeps areas that could interact on the same worker. Separate regions can run in parallel. Packets, lifecycle callbacks, saves, and other shared work still go through the main thread.

The region map changes with the world. Regions form, merge, split, and disappear as chunks load and unload.

Regional TPS: slicing instead of skipping

Tessellate measures every region each tick. If the server is about to miss its tick-time target, the most expensive region gets a tick divisor. A divisor of 4 runs that region at 5 TPS while unaffected regions can stay at 20.

Running the whole region once every fourth tick would produce the right average rate, but it feels awful in play. Tessellate spreads that work across every tick instead:

The trade-off

Throttling has an intentional cost. When a region exceeds its share, everything inside it runs slower. Mobs move more slowly, farms produce less, and hoppers move fewer items. That is useful for containing a lag machine, but Tessellate cannot tell one apart from a legitimately busy base.

If you would rather let the whole server fall below 20 TPS, disable adaptive throttling:

[regions]
adaptiveThrottling = false

Region tracking, parallel ticking, and diagnostics remain available.

Configuration

Settings are stored in config/tessellate-common.toml.

For a serial diagnostic mode:

[regions]
parallelTicking = false
asyncRegionLoops = false

Commands

• /tessellate regions: shows the region map, cost, tick rate, and execution mode
• /tessellate phases: reports worker/main-thread boundaries, timing, failures, and queue depth
• /tessellate violations: reports thread-ownership violations; this should remain empty
• /tessellate visualize: toggles the region map and boundary visualization

Compatibility

We tested independent region loops with:

• NeoForge alone
• Lithium 0.15.4
• Mekanism and Mekanism Generators 10.7.19.85
• Naturalist 2.0.3, Citadel 2.7.1, Friends & Foes 4.0.27, Resourceful Lib 3.0.12, and ScalableLux 0.3.0-alpha.0.8
• C2ME 0.4.0-alpha.0.120 with the full mod set above

Lithium needs a little special handling, so Tessellate replaces two of its level-wide caches with worker-safe equivalents. C2ME is optional. Tessellate runs without it and has no hard dependency on it.

Compatibility reports and automatic fixes

Parallel ticking can expose problems in mods that assume every entity or block entity runs on the main server thread. When Tessellate detects one of these failures, it falls back to a safer execution mode and records the details in the normal server log.

Server owners can also choose to send a small compatibility report. The goal is to find repeatable mod conflicts without asking people to upload entire logs or spend hours testing different configuration changes.

A report may include:

• The Minecraft, Tessellate, and mod loader versions
• Installed mod IDs and versions
• The part of Tessellate that encountered the problem
• The failure class
• The suspected mod and one relevant code location
• The entity or block entity type involved, when known

Reports do not include raw server logs, server addresses, world names, player names, chat, coordinates, or player data.

The upload service does not store your IP address with the report. It creates a one-way rate-limit value so one server cannot flood the database.

Reports are treated as clues, not automatic decisions. A report cannot block a mod or create a compatibility rule. Reports are grouped and reviewed by the Tessellate maintainer first. A confirmed problem can then be fixed upstream, patched in Tessellate, or added as a version-specific compatibility rule.

For example, if a mob is broken in mod version 1.1 but fixed in 1.2, the rule can apply only to 1.1. Players using 1.2 will keep normal parallel ticking.

Compatibility rules can:

• Move a specific entity or block entity to the main thread
• Prevent entity tick bodies from overlapping
• Disable parallel natural spawning for a specific mod
• Use serial region ticking when the problem cannot be isolated further

Remote rules can only reduce concurrency. They cannot enable features, change worlds, run commands, or upload data.

Opting out

Compatibility reporting is off by default. When reportEndpoint is blank, nothing is uploaded and failures are only written to the local server log.

To explicitly disable reporting:

[compatibility]
reportEndpoint = ""
reportApiKey = ""

Remote compatibility rules are separate from reporting. Tessellate checks a public, read-only rules list at startup so known problems can be handled automatically.

To disable the remote rules check:

[compatibility]
rulesEndpoint = ""
rulesApiKey = ""

If the compatibility service is unavailable, Tessellate continues starting normally and uses the local configuration. A failed report upload also has no effect on the server.

What we tested

What it cannot do

• Tessellate protects the shared state it knows about, but another mod can still introduce a race through its own global state. Tessellate falls back to serial ticking when it detects an ownership violation.
• C2ME 0.4.0-alpha.0.120 passes live benchmarks, save/unload, restart, and shutdown testing, but its natural-spawning GameTest fails in both serial and parallel regional modes.
• One hot connected region cannot use another core under the current ownership model.
• Benchmark results are workload-specific and hardware-specific.

Incompatible

• Bukkit-Neoforge/Fabric Hybrids (ex Arclight) - it will load but support is limited as bukkit has very very bad threaded support.