MinecraftServerNetwork VS spark

I'm not sure how much of the built in JFR a mod for Minecraft called Spark uses but it is a fairly common tool for debugging and visualising lag on modded servers https://spark.lucko.me/

G:\DedicatedServers\test>java -Xms10G -Xmx10G -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 -Dusing.aikars.flags=https://mcflags.emc.gs -Daikars.new.flags=true -jar paper-1.20.2-291.jar --nogui Starting org.bukkit.craftbukkit.Main System Info: Java 17 (OpenJDK 64-Bit Server VM 17.0.2+8-86) Host: Windows 10 10.0 (amd64) Loading libraries, please wait... [13:37:15 INFO]: Environment: Environment[accountsHost=https://api.mojang.com, sessionHost=https://sessionserver.mojang.com, servicesHost=https://api.minecraftservices.com, name=PROD] [13:37:15 INFO]: Found new data pack file/bukkit, loading it automatically [13:37:16 INFO]: Loaded 7 recipes [13:37:16 INFO]: Starting minecraft server version 1.20.2 [13:37:16 INFO]: Loading properties [13:37:16 INFO]: This server is running Paper version git-Paper-291 (MC: 1.20.2) (Implementing API version 1.20.2-R0.1-SNAPSHOT) (Git: ce7f068) [13:37:17 INFO]: Using 4 threads for Netty based IO [13:37:17 INFO]: Server Ping Player Sample Count: 12 [13:37:17 INFO]: [ChunkTaskScheduler] Chunk system is using 1 I/O threads, 6 worker threads, and gen parallelism of 6 threads [13:37:17 WARN]: [!] The timings profiler has been enabled but has been scheduled for removal from Paper in the future. We recommend installing the spark profiler as a replacement: https://spark.lucko.me/ For more information please visit: https://github.com/PaperMC/Paper/issues/8948 [13:37:18 INFO]: Default game type: SURVIVAL [13:37:18 INFO]: Generating keypair [13:37:18 INFO]: Starting Minecraft server on *:25555 [13:37:18 INFO]: Using default channel type [13:37:18 INFO]: Paper: Using Java compression from Velocity. [13:37:18 INFO]: Paper: Using Java cipher from Velocity. [13:37:18 INFO]: Preparing level "world" [13:37:22 INFO]: Preparing start region for dimension minecraft:overworld [13:37:22 INFO]: Time elapsed: 52 ms [13:37:22 INFO]: Preparing start region for dimension minecraft:the_nether [13:37:22 INFO]: Time elapsed: 29 ms [13:37:22 INFO]: Preparing start region for dimension minecraft:the_end [13:37:22 INFO]: Time elapsed: 28 ms [13:37:22 INFO]: Running delayed init tasks [13:37:22 INFO]: Done (6.045s)! For help, type "help" [13:37:22 INFO]: Timings Reset

We recommend installing the spark profiler as a replacement: https://spark.lucko.me/

You should run the Spark profiler and come back here with the result.

Use spark. It should come preinstalled with PurpurMC.

Got a spark report? These reports can help you figure out what's taking the most time in your tick loop.

Lowering your simulation distance will probably help quite a bit -- 12 is quite large. If you're running on 1.19, villagers may be a source of lag, however, I would first check with spark to see what specifically is causing lag.

I would take the debug piechart with a grain of salt (it's very easy for mods to get it into a messed up state where a section is opened but not closed, miscategorizing all the events that happen after it). The best profiler is spark. When you experience performance issues, do a spark profile for a minute or two

You can use something like spark to try and diagnose the issue, although I think it’s kinda complex.