new: turn fluid postprocessing into scheduled tick

c2me-rewrites-chunk-system/src/main/java/com/ishland/c2me/rewrites/chunksystem/MixinPlugin.java

@@ -1,6 +1,7 @@
 package com.ishland.c2me.rewrites.chunksystem;
 
 import com.ishland.c2me.base.common.ModuleMixinPlugin;
+import com.ishland.c2me.rewrites.chunksystem.common.Config;
 
 import java.lang.reflect.Field;
 
@@ -16,7 +17,8 @@ public boolean shouldApplyMixin(String targetClassName, String mixinClassName) {
         if (mixinClassName.startsWith("com.ishland.c2me.rewrites.chunksystem.mixin.serialization_sync."))
             return !gcFreeChunkSerializerDetected;
 
-
+        if (mixinClassName.startsWith("com.ishland.c2me.rewrites.chunksystem.mixin.fluid_postprocessing"))
+            return Config.fluidPostProcessingToScheduledTick;
 
         return true;
     }

c2me-rewrites-chunk-system/src/main/java/com/ishland/c2me/rewrites/chunksystem/common/Config.java

@@ -58,6 +58,17 @@ Whether to allow POIs (Point of Interest) to be unloaded
                     """)
             .getBoolean(true, false);
 
+    public static final boolean fluidPostProcessingToScheduledTick = new ConfigSystem.ConfigAccessor()
+            .key("chunkSystem.fluidPostProcessingToScheduledTick")
+            .comment("""
+                    Whether to turn fluid postprocessing into scheduled tick
+                    
+                    Fluid post-processing is very expensive when loading in new chunks, and this can affect
+                    MSPT significantly. This option delays fluid post-processing to scheduled tick to hopefully
+                    mitigate this issue.
+                    """)
+            .getBoolean(true, false);
+
     public static void init() {
         // intentionally empty
     }

c2me-rewrites-chunk-system/src/main/java/com/ishland/c2me/rewrites/chunksystem/mixin/fluid_postprocessing/MixinWorldChunk.java

@@ -0,0 +1,20 @@
+package com.ishland.c2me.rewrites.chunksystem.mixin.fluid_postprocessing;
+
+import net.minecraft.block.BlockState;
+import net.minecraft.fluid.FluidState;
+import net.minecraft.server.world.ServerWorld;
+import net.minecraft.util.math.BlockPos;
+import net.minecraft.world.chunk.WorldChunk;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.injection.At;
+import org.spongepowered.asm.mixin.injection.Redirect;
+
+@Mixin(WorldChunk.class)
+public class MixinWorldChunk {
+
+    @Redirect(method = "runPostProcessing", at = @At(value = "INVOKE", target = "Lnet/minecraft/fluid/FluidState;onScheduledTick(Lnet/minecraft/server/world/ServerWorld;Lnet/minecraft/util/math/BlockPos;Lnet/minecraft/block/BlockState;)V"))
+    private void redirectFluidScheduledTick(FluidState instance, ServerWorld world, BlockPos pos, BlockState state) {
+        world.scheduleFluidTick(pos, instance.getFluid(), 1);
+    }
+
+}

c2me-rewrites-chunk-system/src/main/resources/c2me-rewrites-chunk-system.mixins.json

@@ -19,6 +19,7 @@
     "async_serialization.MixinChunkSerializer",
     "async_serialization.MixinProtoChunk",
     "async_serialization.MixinStorageIoWorker",
-    "async_serialization.MixinThreadedAnvilChunkStorage"
+    "async_serialization.MixinThreadedAnvilChunkStorage",
+    "fluid_postprocessing.MixinWorldChunk"
   ]
 }