[Bug] Multithreaded World Generation on Paper 1.21.3

Question

[Bug] Multithreaded World Generation on Paper 1.21.3

viktordanov opened this issue 7 days ago · 2 comments

viktordanov commented 7 days ago

Pre-Issue Checklist

I have checked that I am on the latest version of Terra. (Running on branch ver/6.6.0 commit 1d3c380)
I have searched the github issue tracker for similar issues, including
closed ones.
I have made sure that this is not a bug with another mod or plugin, and it
is Terra that is causing the issue.
I have checked that this is an issue with Terra and not an issue with the
pack I am using.
I have attached a copy of the latest.log file
I have filled out and provided all the appropriate information.

Environment

Name	Value
Terra Version	ver 6.6.0 commit `1d3c380` (last commit at the time of writing)
Platform / Platform Version	Paper 1.21.3 Build 15 With MultiVerse
Any External Plugins or Mods	Multiverse-Core (4.3.13)
Terra Packs In Use	https://github.com/PolyhedralDev/TerraOverworldConfig from 2.0 Branch (last commit)
Terra Addons In Use	All default addons which are preinstalled on a fresh Terra run

Issue Description

Terrain Generation used to be extremely quick. A few months ago I upgraded my hardware and reconfigured Paper to try to max out my CPU for the fastest generation.
My paper-global.yml

_version: 29
block-updates:
  disable-chorus-plant-updates: false
  disable-mushroom-block-updates: false
  disable-noteblock-updates: false
  disable-tripwire-updates: false
chunk-loading:
  autoconfig-send-distance: true
  enable-frustum-priority: true
  global-max-chunk-load-rate: -1.0
  global-max-chunk-send-rate: -1.0
  global-max-concurrent-loads: 800.0
  max-concurrent-sends: 24
  min-load-radius: 4
  player-max-chunk-load-rate: -1.0
  player-max-concurrent-loads: 30.0
  target-player-chunk-send-rate: 400.0
chunk-loading-advanced:
  auto-config-send-distance: true
  player-max-concurrent-chunk-generates: 320
  player-max-concurrent-chunk-loads: 320
chunk-loading-basic:
  player-max-chunk-generate-rate: 200.0
  player-max-chunk-load-rate: 400.0
  player-max-chunk-send-rate: 400.0
chunk-system:
  gen-parallelism: 'true'
  io-threads: 24
  worker-threads: 28

My start-up params: java -Xms20G -Xmx20G -XX:+UseG1GC -XX:+ParallelRefProcEnabled -XX:MaxGCPauseMillis=200 -XX:+UnlockExperimentalVMOptions -XX:+DisableExplicitGC -XX:+AlwaysPreTouch -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 -DPaper.WorkerThreadCount=28 -Dusing.aikars.flags=https://mcflags.emc.gs -Daikars.new.flags=true -agentlib:jdwp=transport=dt_socket,server=y,suspend=n,address=*:5050 -jar paper-1.21.3-15.jar --nogui

Since my upgrade to 1.21.3 from 1.21.1 Terra Worlds started generating very slowly with minimal CPU usage.

Ablation tests for issue isolation

Normal Minecraft world generation is using all allocated cores [Fast]
Using other generators with Multiverse-Core (tested random plugins from spigotmc and modrinth [Fast]
Tested default.zip with Terra [Slow]
Tested the OverworldConfig pack with Terra [Slow]

Steps to reproduce

Generate new world / enter existing
Fly around to generate new chunks
Observe CPU usage and visible chunk generation speed

Expected behavior

All allocated cores should be used.

Actual behavior

Only 1 or no more than 4 are used (difficult to discern).

viktordanov · Answer 1 · 2024-11-09T10:35:08.000Z

latest.log

viktordanov · Answer 2 · 2024-11-09T11:23:05.000Z

I identified part of the problem:

In platforms/bukkit/common/src/main/.../PlatformImpl.java

    public PlatformImpl(TerraBukkitPlugin plugin) {
        generationThreads = getGenerationThreadsWithReflection("ca.spottedleaf.moonrise.common.util.MoonriseCommon", "WORKER_THREADS", "Moonrise");
        System.out.println("Generation threads: " + generationThreads);
        if (generationThreads == 0) {
            generationThreads = 1;
            System.out.println("Failed to get generation threads, defaulting to 1.");
        }
        this.plugin = plugin;
        load();
    }

I get these logs:

[11:05:41 WARN]: [com.dfsek.terra.AbstractPlatform] Moonrise found, but WORKER_THREADS field not found this probably means {0} has changed its code and Terra has not updated to reflect that.
[11:05:41 INFO]: [STDOUT] [com.dfsek.terra.bukkit.PlatformImpl] Generation threads: 0
[11:05:41 INFO]: [STDOUT] [com.dfsek.terra.bukkit.PlatformImpl] Failed to get generation threads, defaulting to 1.
[11:05:41 INFO]: [com.dfsek.terra.AbstractPlatform] Initializing Terra...
[11:05:41 INFO]: [com.dfsek.terra.AbstractPlatform] Loading config.yml
[11:05:41 INFO]: [com.dfsek.terra.config.PluginConfigImpl] Loading config values from config.yml
[11:05:41 INFO]: [com.dfsek.terra.AbstractPlatform] Loading 39 Terra addons:
        - [email protected]+65e4c9a14
        - [email protected]+65e4c9a14
        ```

Check https://github.com/Tuinity/Moonrise/blob/ea50ba38eada4c852a52f9bc3fd0960bcf57c39b/src/main/java/ca/spottedleaf/moonrise/common/util/MoonriseCommon.java#L47

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