From 7c3c830d6e6eb414cbd6e5851b8ca56bfbb1fa6c Mon Sep 17 00:00:00 2001
From: h7x4 <h7x4@nani.wtf>
Date: Sat, 25 Feb 2023 21:15:35 +0100
Subject: [PATCH] tsuki: add recommended minecraft jvm flags

---
 hosts/tsuki/services/minecraft/default.nix | 26 +++++++++++++++++++++-
 1 file changed, 25 insertions(+), 1 deletion(-)

diff --git a/hosts/tsuki/services/minecraft/default.nix b/hosts/tsuki/services/minecraft/default.nix
index d8a1593..008e8fa 100644
--- a/hosts/tsuki/services/minecraft/default.nix
+++ b/hosts/tsuki/services/minecraft/default.nix
@@ -69,7 +69,31 @@
 
       package = inputs.minecraft.packages.x86_64-linux.paper-server;
 
-      jvmOpts = "-Xmx5G -Xms5G -XX:+UseG1GC";
+      # See https://docs.papermc.io/paper/aikars-flags
+      jvmOpts = lib.concatStringsSep " " [
+        "-Xms5G"
+        "-Xmx15G"
+        "-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"
+      ];
 
       symlinks = let
         rawFile = file: pkgs.runCommandLocal (builtins.baseNameOf file) {} ''