Print a warning if G1GC is used

G1GC is known to cause stuttering

core/src/main/java/com/seibel/distanthorizons/core/Initializer.java

@@ -25,23 +25,16 @@ import com.seibel.distanthorizons.core.logging.DhLoggerBuilder;
 import com.seibel.distanthorizons.core.render.renderer.generic.GenericRenderObjectFactory;
 import com.seibel.distanthorizons.core.sql.DatabaseUpdater;
 import com.seibel.distanthorizons.core.wrapperInterfaces.IWrapperFactory;
-import com.seibel.distanthorizons.core.wrapperInterfaces.minecraft.IMinecraftClientWrapper;
-import com.seibel.distanthorizons.coreapi.ModInfo;
 import com.seibel.distanthorizons.core.world.DhApiWorldProxy;
 import com.seibel.distanthorizons.core.api.external.methods.config.DhApiConfig;
 import com.seibel.distanthorizons.core.api.external.methods.data.DhApiTerrainDataRepo;
 import com.seibel.distanthorizons.api.DhApi;
 import com.seibel.distanthorizons.core.render.DhApiRenderProxy;
 import net.jpountz.lz4.LZ4FrameOutputStream;
-import org.apache.logging.log4j.LogManager;
 import com.seibel.distanthorizons.core.logging.DhLogger;
 import org.sqlite.SQLiteJDBCLoader;
-import org.sqlite.util.OSInfo;
 import org.tukaani.xz.XZOutputStream;
 
-import java.awt.*;
-import java.io.File;
-
 /** Handles first time Core setup. */
 public class Initializer
 {

core/src/main/java/com/seibel/distanthorizons/core/api/internal/ClientApi.java

@@ -56,6 +56,8 @@ import org.jetbrains.annotations.Nullable;
 import org.lwjgl.glfw.GLFW;
 
 import java.io.File;
+import java.lang.management.GarbageCollectorMXBean;
+import java.lang.management.ManagementFactory;
 import java.util.*;
 import java.util.concurrent.LinkedBlockingQueue;
 
@@ -93,6 +95,7 @@ public class ClientApi
 	private boolean isDevBuildMessagePrinted = false;
 	private boolean lowMemoryWarningPrinted = false;
 	private boolean highVanillaRenderDistanceWarningPrinted = false;
+	private boolean g1GarbageCollectorWarningPrinted = false;
 	
 	private long lastStaticWarningMessageSentMsTime = 0L;
 	
@@ -645,7 +648,8 @@ public class ClientApi
 	{
 		// dev build
 		if (ModInfo.IS_DEV_BUILD 
-			&& !this.isDevBuildMessagePrinted && MC_CLIENT.playerExists())
+			&& !this.isDevBuildMessagePrinted 
+			&& MC_CLIENT.playerExists())
 		{
 			this.isDevBuildMessagePrinted = true;
 			this.lastStaticWarningMessageSentMsTime = System.currentTimeMillis();
@@ -691,10 +695,11 @@ public class ClientApi
 		if (!this.highVanillaRenderDistanceWarningPrinted 
 			&& Config.Common.Logging.Warning.showHighVanillaRenderDistanceWarning.get())
 		{
+			this.highVanillaRenderDistanceWarningPrinted = true;
+			
 			// DH generally doesn't need a vanilla render distance above 12 
 			if (MC_RENDER.getRenderDistance() > 12)
 			{
-				this.highVanillaRenderDistanceWarningPrinted = true;
 				this.lastStaticWarningMessageSentMsTime = System.currentTimeMillis();
 				
 				String message =
@@ -710,6 +715,48 @@ public class ClientApi
 				MC_CLIENT.sendChatMessage(message);
 			}
 		}
+		
+		
+		// print a warning if G1GC is being used
+		// (this garbage collector is known to cause stuttering)
+		if (this.staticStartupMessageSentRecently()) return;
+		if (!this.g1GarbageCollectorWarningPrinted
+			&& Config.Common.Logging.Warning.showGarbageCollectorWarning.get())
+		{
+			this.g1GarbageCollectorWarningPrinted = true;
+			
+			try
+			{
+				boolean g1GcInUse = false;
+				
+				List<GarbageCollectorMXBean> gcMxBeans = ManagementFactory.getGarbageCollectorMXBeans();
+				for (GarbageCollectorMXBean gcMxBean : gcMxBeans)
+				{
+					// "G1 Young Generation" // "G1 Concurrent GC" // "G1 Old Generation"
+					if (gcMxBean.getName().toLowerCase().contains("g1 "))
+					{
+						g1GcInUse = true;
+						break;
+					}
+				}
+				
+				if (g1GcInUse)
+				{
+					ClientApi.INSTANCE.showChatMessageNextFrame(
+						// yellow text
+						"\u00A7e" + "Distant Horizons: G1 Garbage collector detected." + "\u00A7r \n" +
+							"This garbage collector can cause FPS stuttering. \n" +
+							"It's recommended to use a concurrent garbage collector \n" +
+							"like ZGC (Java 21+) for a smoother experience. \n" +
+							"");
+				}
+			}
+			catch (Exception re)
+			{
+				LOGGER.warn("Unable to determine garbage collector type. If stuttering occurs please try a concurrent garbage collector like ZGC.");
+			}
+		}
+		
 	}
 	/** done to prevent sending a bunch of startup messages all at once, causing some to be missed. */
 	private boolean staticStartupMessageSentRecently()

core/src/main/java/com/seibel/distanthorizons/core/config/Config.java

@@ -1629,6 +1629,15 @@ public class Config
 								+ "")
 						.build();
 				
+				public static ConfigEntry<Boolean> showGarbageCollectorWarning = new ConfigEntry.Builder<Boolean>()
+						.set(true)
+						.comment(""
+								+ "If enabled, a chat message will be displayed if the garbage \n"
+								+ "collector Java is currently using is known \n"
+								+ "to cause stutters and/or issues. \n"
+								+ "")
+						.build();
+				
 				public static ConfigEntry<Boolean> showReplayWarningOnStartup = new ConfigEntry.Builder<Boolean>()
 						.set(true)
 						.comment(""

core/src/main/resources/assets/distanthorizons/lang/en_us.json

@@ -725,6 +725,8 @@
     "If DH detects that pooled objects are being garbage collected this will send a chat warning.",
   "distanthorizons.config.common.logging.warning.showHighVanillaRenderDistanceWarning":
     "Show High Vanilla Render Distance Warning",
+  "distanthorizons.config.common.logging.warning.showGarbageCollectorWarning":
+    "Show Garbage Collector Warning",
   "distanthorizons.config.common.logging.warning.showReplayWarningOnStartup":
     "Show Replay Warning",
   "distanthorizons.config.common.logging.warning.showUpdateQueueOverloadedChatWarning":