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Modrinth · Minecraft mod

KAllFix

Optimization and multithreading written by n1luik

Choose a version Pick your version below, then grab the matching file.

Quick answer

Which KAllFix release should I use?

Updated 2 days ago
Latest stable file 1.0.3.14
Game version 1.20.1
Loader Forge

KAllFix 1.0.3.14 targets 1.20.1 with Forge. Installation on the client is optional. Installation on the dedicated server is optional. No extra mods listed for this file.

Where it goes

Is KAllFix required on the client, server, or both?

Installation on the client is optional. Installation on the dedicated server is optional.

Client Optional
Dedicated server Optional
Loader for this release Forge
Required install it here Optional supported, not mandatory Not supported do not install here Source doesn’t say do not assume

The source marks this as usable on both the client and server.

What else does KAllFix 1.0.3.14 need?

1.0.3.14. Change the file and its required mods may change too.

No extra mods listed for this file

This file does not list any required mods. Do not add a library just because a different file uses it.

This file does not list any required or optional mods.

Before you install it

Add KAllFix without breaking your instance.

Built for KAllFix 1.0.3.14. Pick another file and the loader, install side or required mods may change.

  1. 01

    Stick to this file

    Use 1.0.3.14. It targets 1.20.1 with Forge; another release may have different loader, side or dependency requirements.

  2. 02

    Bring the mods it needs

    This file does not list any required mods. Do not add a library just because a different file uses it.

  3. 03

    Put it on the correct side

    Installation on the client is optional. Installation on the dedicated server is optional.

  4. 04

    Pick the file you checked

    Use the “Get this file” button beside 1.0.3.14. It opens that exact file at the source.

About this project

What does KAllFix add?

Overview

  • This project is used to fix and optimize issues caused by other mods, and it works on servers.
  • The project contains two main parts: k_all_fix and k_multi_threading, with features mainly controlled by JVM parameters.
  • No regular config file is provided; configuration is mainly done through startup parameters.
  • Client-side usage is supported from 1.0.4.0 onward (requires JVM parameter -DKMT_Client=true).
  • Under a multi-mod and single-threaded baseline environment, cause no issues is not guaranteed, but you could create an ISSUE on Github and the author will fix it quickly.
  • With some mod combinations, clients may still need to install this mod even if it has no visible effect.

Features and Use Cases

Optimizations

Fixes

Multithreading

Introduction

  • Multithreading supports includes block ticks, block entity ticks, entities, dimensions, player packet receiving (manual toggle, client-only), and player login (manual toggle), and also fixes some problematic single-threaded mods by applying multithreading.
  • Multithreading is enabled by default on the server side.
  • In multithreaded scenarios, thread-pool interception or limit-exceeded errors may appear, but they usually do not crash the server.
  • It is recommended to manually set -DKMT-threadMax=[CPU thread count]; otherwise world generation may be frozen. If freezes still occurs after setting it, increase the value higher.
  • Before 1.0.4.0, clients cannot use multithreading; from 1.0.4.0 onward, clients can enable it via -DKMT_Client=true.
  • After 1.0.3.3, ParaServerChunkProvider, TaskRun, and some chunk generation code depend more heavily on C2 compilation (the JVM will enter C2 automatically after running for a while).
  • In Windows Server 2022 Datacenter 21H2 20348.3091 (author's environment), rare thread scheduling anomalies may occur and causes abnormally high CPU usage; the solution is to restart the server.

Related JVM Parameters

  • -DKMT-threadMax=[number]
    • Sets thread-pool thread count.
  • -DKMT-callMax=[number]
    • Sets the default maximum number of threads that multithreaded tasks may use.
  • -DKMT-ThreadpoolKeepAliveTime=[milliseconds]
    • Sets how long idle threads are kept before recycling.
  • -DKMT_D=[any characters]
    • Disables multithreading.
  • -DKMT-OpenVanillaServerChunkCache=true
    • Forces the vanilla ServerChunkCache fix path (added in 1.0.5.3).

JVM Parameter Overview (all retained)

Basic and General

  • -DKAllFix_D=[any characters]
    • Disables KAllFix.
  • -DKMT_Client=true
    • Enables multithreading-related features on the client side (1.0.4.0+).
  • -DKAF-DisablePetrolpark=false

Connection and Timeout

  • -DKAF-ClientboundKeepAlivePacket_Max=[milliseconds]
    • Changes the timing requirement for ClientboundKeepAlivePacket (default 15 seconds; vanilla must be <30 seconds or the player is kicked for timeout).
  • -DKAF-ServerTimeout=[seconds]
    • Sets server connection timeout.
    • May be ineffective in some cases (both parameters are needed because Forge's forge.readTimeout only covers server packet-read timeout, not client/server network threads with players).
  • -Dforge.readTimeout=[seconds]
    • Forge packet-read timeout parameter (used together with the previous parameter).

Mixin / NBT / Auto Command

  • -DKAF-RemoveMixin:[class name]
    • Disables a specified mixin (k_multi_threading mixins can also be disabled).
  • -DKAF-NbtIoMixin_NotGZip=true
    • Adds try-catch to NBT IO for non-gzip scenarios (unsafe; requires commons-compress in the environment).
  • -DKMT-ChunkGeneratorMode2Start=[true,false]
    • Automatically runs: /SetterWorldConfig world setM2 %%KMT-ChunkGeneratorMode2Start%%.

Breeding Control

  • -DKAF-ChunkBreedingControlSize=[number]
    • Disables breeding when chunk entity count exceeds the given value; disabled if the parameter is missing / not a numeric array / empty.
  • -DKAF-ChunkBreedingControlSizeEnable=[true,false]
    • Internal cache switch for detection results; manual setting may be overridden by the program.

Optional Features

  • -DKMT-SafeUnloadChunk=true
    • Enables chunk unload in chunk-generation threads (recommended only for <1.0.4.2 when related freezes occur).
  • -DIndependencePlayer=true
    • Enables asynchronous player handling (likely provides little to no optimization).
  • -DFixBiolithBugMode2=true
    • Attempts to fix most Biolith compatibility issues (may introduce major bugs).
  • -DKAF-gtceu.MedicalConditionTrackerMixin=true
    • Disables radiation in GTM.
  • -DKAF-RemoveClientboundKeepAlivePacket=true
    • Disables vanilla ClientboundKeepAlivePacket (ping can no longer be calculated).
  • -DKAF-RemoveFlyingTest=true
    • Removes flight checks.
  • -DKAF-moonrise_fast_palette=true
    • Disable the fast_palette feature from Moonrise.
  • -DKAF-FixTFMGDestroy=true
    • Fixes compatibility between Destroy and Create (Creative Pump cannot properly connect to Create's pipes).
  • -DKAF-Fix_fabric-object-builder-api.jar=true
    • Fixes compatibility between Sinytra Connector's fabric-object-builder-api and forge-47.3.27.
  • -DKAF-FixAllPacket=true
  • -DKAF-ChunkAwareBlockCollisionSweeperFast=true
    • Use approximation algorithm to replace ChunkAwareBlockCollisionSweeper of Lithium

Login Multithreading

  • -DKMT-LoginMultiThreading=true
    • Enables multithreaded login.
  • -DKMT-LoginMultiThreading.ConnectionLock=true
    • Waits for async execution completion at tick end (disabling may improve performance somewhat, but lowers login stability and may crash).
  • -DKMT-LoginMultiThreading.TaskSizeMax=[number]
    • Limits the number of concurrent login tasks (default 8).
  • Login multithreading may cause the server to receive ServerboundMovePlayerPacket early, leading to one error log.

Packet Optimization

  • -DKAF-packetOptimize=true
    • Optimizes some vanilla packets (must be enabled on both client and server).
  • -DKAF-packetOptimize.AttributesReOutputTime=[milliseconds]
    • Sets forced resend interval for attribute-related data (default 2 minutes).
  • -DKAF-packetOptimize.CompatibilityMode.ClientboundBlockEntityDataPacket=true
    • Uses more conservative compression for ClientboundBlockEntityDataPacket (impacts performance).
  • -DKAF-packetOptimize.CompatibilityMode.ClientboundSectionBlocksUpdatePacket=true
    • Uses more conservative compression for ClientboundSectionBlocksUpdatePacket.

Others

  • -DKAF-UnsafeCinderscapesFix1=true
    • Adjusts limits for the high-overhead enableAshFall function in Cinderscapes.
  • -DKAF-fix.asynchronous.ClientboundCustomQueryPacket=true
    • Makes handshake asynchronous, reducing the chance of being unable to join when too many mods are installed.
  • -DKAF-FixConfigAuto=true
    • Automatically changes some config options for compatibility.

Installation and Runtime Notes

  • From 1.0.3.18, it can run directly (installation feature is still kept).
  • Before 1.0.3.18, run the mod's installer first, or use:
    • java -jar k_multi_threading-xxx.jar -i [empty or install directory]
  • Installation only generates k_multi_threading-base.jar and k_multi_threading-asm.jar.
  • Some features may download dependencies (Zstd-jni 1.5.7-2); if download fails, place them manually in game_directory/lib.

Compatibility Notes

  • Using -DKAF-FixConfigAuto=true can automatically disable:
    • logOffthreadEntityAdd in Cupboard.
    • world.tick_scheduler and entity_by_type in Canary / Lithium (you must manually add mixin.world.tick_scheduler=false in config/canary.properties or config/lithium.properties; otherwise these mod will override the multithread fix for ClassInstanceMultiMap).
  • Cases where -DKAF-FixConfigAuto=true should not be used:
    • Possible conflict with mixin.perf.cache_upgraded_structures in ModernFix (disable via mixin.perf.cache_upgraded_structures=false in config/modernfix-mixins.properties).
    • With login multithreading enabled, ParCool (listed as Parkour on page) may require one death after player joining before working normally.
    • Ars Creo may rarely log Modifier is already applied on this attribute!, but will not crash.
    • NuclearCraft: Neoteric fission reactors may rarely calculate cooling incorrectly after server restart.

Commands

  • /debug_GetterClassFile [class name]

    • Exports final runtime class data to the game directory, with filename format timestamp_save.class.
  • /SetterWorldConfig [world, ClearErrorSize, RemoveRemoveErrorSize]

    • Settings from this command are not persistent.
    • ClearErrorSize: clears the recorded count of “errors that caused server crash risk”.
    • RemoveRemoveErrorSize: stops recording crash-risk counts and keeps intercepting.
    • Under world [dimension registry id], available options:
      • setM2 [true,false]: switches to another dimension implementation mode; higher priority than setMultiThreading, but may freeze the game.
      • setMultiThreading [number] (default 0): sets multithread parallel task count for this dimension; independent mode from setM2, and may also freeze the game.

Others

  • Because Minecraft and many mods are fundamentally designed around single-threaded behavior, complete fixes for all issues cannot be guaranteed.

Source Code Usage

Project description from Modrinth.

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KAllFix by Minecraft version and loader

Choose the version and loader you play, then open the matching release.

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KAllFix versions and loaders

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Looking for an older file? The official Modrinth project page is in Resources.