Add support for throttling chunk load rate, spreading over ticks

configuration.txt

@@ -100,6 +100,9 @@ disable-webserver: false
 # Period between tile renders for fullrender, in seconds (non-zero to pace fullrenders, lessen CPU load)
 timesliceinterval: 0.0
 
+# Maximum chunk loads per server tick (1/20th of a second) - reducing this below 90 will impact render performance, but also will reduce server thread load
+maxchunkspertick: 200
+
 # Interval the browser should poll for updates.
 updaterate: 2000
 

src/main/java/org/dynmap/MapManager.java

@@ -9,10 +9,10 @@ import java.util.LinkedList;
 import java.util.List;
 import java.util.Map;
 import java.util.TreeSet;
+import java.util.concurrent.ConcurrentLinkedQueue;
 import java.util.concurrent.ScheduledThreadPoolExecutor;
+import java.util.concurrent.ThreadFactory;
 import java.util.concurrent.TimeUnit;
-import java.util.concurrent.Callable;
-import java.util.concurrent.Future;
 import org.bukkit.Location;
 import org.bukkit.World;
 import org.bukkit.scheduler.BukkitScheduler;
@@ -25,13 +25,18 @@ import org.dynmap.utils.NewMapChunkCache;
 public class MapManager {
     public AsynchronousQueue<MapTile> tileQueue;
 
+    private static final int DEFAULT_CHUNKS_PER_TICK = 200;
+    
     public List<DynmapWorld> worlds = new ArrayList<DynmapWorld>();
     public Map<String, DynmapWorld> worldsLookup = new HashMap<String, DynmapWorld>();
     private BukkitScheduler scheduler;
     private DynmapPlugin plug_in;
     private long timeslice_int = 0; /* In milliseconds */
+    private int max_chunk_loads_per_tick = DEFAULT_CHUNKS_PER_TICK;
     /* Which fullrenders are active */
     private HashMap<String, FullWorldRenderState> active_renders = new HashMap<String, FullWorldRenderState>();
+    /* List of MapChunkCache requests to be processed */
+    private ConcurrentLinkedQueue<MapChunkCache> chunkloads = new ConcurrentLinkedQueue<MapChunkCache>();
     /* Tile hash manager */
     public TileHashManager hashman;
     /* lock for our data structures */
@@ -61,9 +66,21 @@ public class MapManager {
         return worlds;
     }
 
+    private static class OurThreadFactory implements ThreadFactory {
+        @Override
+        public Thread newThread(Runnable r) {
+            Thread t = new Thread(r);
+            t.setDaemon(true);
+            t.setPriority(Thread.MIN_PRIORITY);
+            t.setName("Dynmap Render Thread");
+            return t;
+        }
+    }
+    
     private class DynmapScheduledThreadPoolExecutor extends ScheduledThreadPoolExecutor {
         DynmapScheduledThreadPoolExecutor() {
             super(POOL_SIZE);
+            this.setThreadFactory(new OurThreadFactory());
         }
 
         protected void afterExecute(Runnable r, Throwable x) {
@@ -163,7 +180,7 @@ public class MapManager {
             }
             World w = world.world;
             /* Fetch chunk cache from server thread */
-            DynmapChunk[] requiredChunks = tile.getMap().getRequiredChunks(tile);
+            List<DynmapChunk> requiredChunks = tile.getMap().getRequiredChunks(tile);
             MapChunkCache cache = createMapChunkCache(world, requiredChunks);
             if(cache == null) {
                 cleanup();
@@ -222,6 +239,25 @@ public class MapManager {
         }
     }
     
+    private class ProcessChunkLoads implements Runnable {
+        public void run() {
+            int cnt = max_chunk_loads_per_tick;
+            
+            while(cnt > 0) {
+                MapChunkCache c = chunkloads.peek();
+                if(c == null)
+                    return;
+                cnt = cnt - c.loadChunks(cnt);
+                if(c.isDoneLoading()) {
+                    chunkloads.poll();
+                    synchronized(c) {
+                        c.notify();
+                    }
+                }
+            }
+        }
+    }
+    
     public MapManager(DynmapPlugin plugin, ConfigurationNode configuration) {
         plug_in = plugin;
         mapman = this;
@@ -235,7 +271,8 @@ public class MapManager {
 
         /* On dedicated thread, so default to no delays */
         timeslice_int = (long)(configuration.getDouble("timesliceinterval", 0.0) * 1000);
-
+        max_chunk_loads_per_tick = configuration.getInteger("maxchunkspertick", DEFAULT_CHUNKS_PER_TICK);
+        if(max_chunk_loads_per_tick < 5) max_chunk_loads_per_tick = 5;
         scheduler = plugin.getServer().getScheduler();
 
         hashman = new TileHashManager(DynmapPlugin.tilesDirectory, configuration.getBoolean("enabletilehash", true));
@@ -247,7 +284,7 @@ public class MapManager {
         }
         
         scheduler.scheduleSyncRepeatingTask(plugin, new CheckWorldTimes(), 5*20, 5*20); /* Check very 5 seconds */
-        
+        scheduler.scheduleSyncRepeatingTask(plugin, new ProcessChunkLoads(), 1, 1); /* Chunk loader task */
     }
 
     void renderFullWorld(Location l, CommandSender sender) {
@@ -439,9 +476,7 @@ public class MapManager {
     /**
      * Render processor helper - used by code running on render threads to request chunk snapshot cache from server/sync thread
      */
-    public MapChunkCache createMapChunkCache(final DynmapWorld w, final DynmapChunk[] chunks) {
+    public MapChunkCache createMapChunkCache(final DynmapWorld w, final List<DynmapChunk> chunks) {
-        Callable<MapChunkCache> job = new Callable<MapChunkCache>() {
-            public MapChunkCache call() {
         MapChunkCache c = null;
         try {
             if(!use_legacy)
@@ -457,18 +492,17 @@ public class MapManager {
             }
             c.setHiddenFillStyle(w.hiddenchunkstyle);
         }
-                c.loadChunks(w.world, chunks);
+        c.setChunks(w.world, chunks);
-                return c;
+        synchronized(c) {
-            }
+            chunkloads.add(c);
-        };
-        Future<MapChunkCache> rslt = scheduler.callSyncMethod(plug_in, job);
             try {
-            return rslt.get();
+                c.wait();
-        } catch (Exception x) {
+            } catch (InterruptedException ix) {
-            Log.info("createMapChunk - " + x);
                 return null;
             }
         }
+        return c;
+    }
     /**
      *  Update map tile statistics
      */

src/main/java/org/dynmap/MapType.java

@@ -1,6 +1,7 @@
 package org.dynmap;
 
 import java.io.File;
+import java.util.List;
 
 import org.bukkit.Location;
 import org.dynmap.utils.MapChunkCache;
@@ -13,7 +14,7 @@ public abstract class MapType {
 
     public abstract MapTile[] getAdjecentTiles(MapTile tile);
 
-    public abstract DynmapChunk[] getRequiredChunks(MapTile tile);
+    public abstract List<DynmapChunk> getRequiredChunks(MapTile tile);
 
     public abstract boolean render(MapChunkCache cache, MapTile tile, File outputFile);
     

src/main/java/org/dynmap/flat/FlatMap.java

@@ -5,6 +5,8 @@ import static org.dynmap.JSONUtils.a;
 import static org.dynmap.JSONUtils.s;
 import java.io.File;
 import java.io.IOException;
+import java.util.ArrayList;
+import java.util.List;
 
 import javax.imageio.ImageIO;
 
@@ -101,18 +103,16 @@ public class FlatMap extends MapType {
     }
 
     @Override
-    public DynmapChunk[] getRequiredChunks(MapTile tile) {
+    public List<DynmapChunk> getRequiredChunks(MapTile tile) {
         FlatMapTile t = (FlatMapTile) tile;
         int chunksPerTile = t.size / 16;
         int sx = t.x * chunksPerTile;
         int sz = t.y * chunksPerTile;
 
-        DynmapChunk[] result = new DynmapChunk[chunksPerTile * chunksPerTile];
+        ArrayList<DynmapChunk> result = new ArrayList<DynmapChunk>(chunksPerTile * chunksPerTile);
-        int index = 0;
         for (int x = 0; x < chunksPerTile; x++)
             for (int z = 0; z < chunksPerTile; z++) {
-                result[index] = new DynmapChunk(sx + x, sz + z);
+                result.add(new DynmapChunk(sx + x, sz + z));
-                index++;
             }
         return result;
     }

src/main/java/org/dynmap/kzedmap/KzedMap.java

@@ -164,7 +164,7 @@ public class KzedMap extends MapType {
         return false;
     }
     @Override
-    public DynmapChunk[] getRequiredChunks(MapTile tile) {
+    public List<DynmapChunk> getRequiredChunks(MapTile tile) {
         if (tile instanceof KzedMapTile) {
             KzedMapTile t = (KzedMapTile) tile;
 
@@ -216,12 +216,9 @@ public class KzedMap extends MapType {
                     chunks.add(chunk);
                 }
             }
-
+            return chunks;
-            DynmapChunk[] result = new DynmapChunk[chunks.size()];
-            chunks.toArray(result);
-            return result;
         } else {
-            return new DynmapChunk[0];
+            return new ArrayList<DynmapChunk>();
         }
     }
 

src/main/java/org/dynmap/utils/LegacyMapChunkCache.java

@@ -2,6 +2,7 @@ package org.dynmap.utils;
 
 import java.lang.reflect.Method;
 import java.util.ArrayList;
+import java.util.ListIterator;
 import java.lang.reflect.Field;
 import org.bukkit.World;
 import org.bukkit.Chunk;
@@ -21,6 +22,10 @@ public class LegacyMapChunkCache implements MapChunkCache {
     private static Field heightmap = null;
     private static boolean initialized = false;
 
+    private World w;
+    private List<DynmapChunk> chunks;
+    private ListIterator<DynmapChunk> iterator;
+
     private int x_min, x_max, z_min, z_max;
     private int x_dim;
     private HiddenChunkStyle hidestyle = HiddenChunkStyle.FILL_AIR;
@@ -177,17 +182,15 @@ public class LegacyMapChunkCache implements MapChunkCache {
     public LegacyMapChunkCache() {
     }
     /**
-     * Create chunk cache container
+     * Set chunks to load, and world to load from
-     * @param w - world
-     * @param x_min - minimum chunk x coordinate
-     * @param z_min - minimum chunk z coordinate
-     * @param x_max - maximum chunk x coordinate
-     * @param z_max - maximum chunk z coordinate
      */
-    @SuppressWarnings({ "unchecked" })
+    @SuppressWarnings({ "rawtypes", "unchecked" })
-    public void loadChunks(World w, DynmapChunk[] chunks) {
+    public void setChunks(World w, List<DynmapChunk> chunks) {
+        this.w = w;
+        this.chunks = chunks;
+
         /* Compute range */
-        if(chunks.length == 0) {
+        if(chunks.size() == 0) {
             this.x_min = 0;
             this.x_max = 0;
             this.z_min = 0;
@@ -195,17 +198,17 @@ public class LegacyMapChunkCache implements MapChunkCache {
             x_dim = 1;            
         }
         else {
-            x_min = x_max = chunks[0].x;
+            x_min = x_max = chunks.get(0).x;
-            z_min = z_max = chunks[0].z;
+            z_min = z_max = chunks.get(0).z;
-            for(int i = 1; i < chunks.length; i++) {
+            for(DynmapChunk c : chunks) {
-                if(chunks[i].x > x_max)
+                if(c.x > x_max)
-                    x_max = chunks[i].x;
+                    x_max = c.x;
-                if(chunks[i].x < x_min)
+                if(c.x < x_min)
-                    x_min = chunks[i].x;
+                    x_min = c.x;
-                if(chunks[i].z > z_max)
+                if(c.z > z_max)
-                    z_max = chunks[i].z;
+                    z_max = c.z;
-                if(chunks[i].z < z_min)
+                if(c.z < z_min)
-                    z_min = chunks[i].z;
+                    z_min = c.z;
             }
             x_dim = x_max - x_min + 1;            
         }
@@ -238,9 +241,17 @@ public class LegacyMapChunkCache implements MapChunkCache {
             }
         }
         snaparray = new LegacyChunkSnapshot[x_dim * (z_max-z_min+1)];
-        if(gethandle != null) {
+    }
+    
+    public int loadChunks(int max_to_load) {
+        int cnt = 0;
+        if(iterator == null)
+            iterator = chunks.listIterator();
+        
         // Load the required chunks.
-            for (DynmapChunk chunk : chunks) {
+        while((cnt < max_to_load) && iterator.hasNext()) {
+            DynmapChunk chunk = iterator.next();
+            if(gethandle != null) {
                 boolean vis = true;
                 if(visible_limits != null) {
                     vis = false;
@@ -302,13 +313,26 @@ public class LegacyMapChunkCache implements MapChunkCache {
                     }
                 }
             }
+            cnt++;
         }
+        /* If done, finish table */
+        if(iterator.hasNext() == false) {
             /* Fill missing chunks with empty dummy chunk */
             for(int i = 0; i < snaparray.length; i++) {
                 if(snaparray[i] == null)
                     snaparray[i] = EMPTY;
             }
         }
+        return cnt;
+    }
+    /**
+     * Test if done loading
+     */
+    public boolean isDoneLoading() {
+        if(iterator != null)
+            return !iterator.hasNext();
+        return false;
+    }
     /**
      * Unload chunks
      */

src/main/java/org/dynmap/utils/MapChunkCache.java

@@ -1,5 +1,6 @@
 package org.dynmap.utils;
 import org.bukkit.World;
+import java.util.List;
 import org.dynmap.DynmapChunk;
 
 public interface MapChunkCache {
@@ -12,11 +13,19 @@ public interface MapChunkCache {
         public int x0, x1, z0, z1;
     }
     /**
-     * Load chunks into cache
+     * Set chunks to load, and world to load from
-     * @param w - world
-     * @param chunks - chunks to be loaded
      */
-    void loadChunks(World w, DynmapChunk[] chunks);
+    void setChunks(World w, List<DynmapChunk> chunks);
+    /**
+     * Load chunks into cache
+     * @param maxToLoad - maximum number to load at once
+     * @return number loaded
+     */
+    int loadChunks(int maxToLoad);
+    /**
+     * Test if done loading
+     */
+    boolean isDoneLoading();
     /**
      * Unload chunks
      */

src/main/java/org/dynmap/utils/NewMapChunkCache.java

@@ -3,6 +3,7 @@ package org.dynmap.utils;
 import java.lang.reflect.Method;
 import java.util.ArrayList;
 import java.util.List;
+import java.util.ListIterator;
 
 import org.bukkit.World;
 import org.bukkit.Chunk;
@@ -18,6 +19,9 @@ import org.dynmap.Log;
 public class NewMapChunkCache implements MapChunkCache {
     private static Method poppreservedchunk = null;
     
+    private World w;
+    private List<DynmapChunk> chunks;
+    private ListIterator<DynmapChunk> iterator;
     private int x_min, x_max, z_min, z_max;
     private int x_dim;
     private HiddenChunkStyle hidestyle = HiddenChunkStyle.FILL_AIR;
@@ -189,16 +193,10 @@ public class NewMapChunkCache implements MapChunkCache {
      */
     public NewMapChunkCache() {
     }
-    /**
-     * Create chunk cache container
-     * @param w - world
-     * @param x_min - minimum chunk x coordinate
-     * @param z_min - minimum chunk z coordinate
-     * @param x_max - maximum chunk x coordinate
-     * @param z_max - maximum chunk z coordinate
-     */
     @SuppressWarnings({ "unchecked", "rawtypes" })
-    public void loadChunks(World w, DynmapChunk[] chunks) {
+    public void setChunks(World w, List<DynmapChunk> chunks) {
+        this.w = w;
+        this.chunks = chunks;
         if(poppreservedchunk == null) {
             /* Get CraftWorld.popPreservedChunk(x,z) - reduces memory bloat from map traversals (optional) */
             try {
@@ -209,7 +207,7 @@ public class NewMapChunkCache implements MapChunkCache {
             }
         }
         /* Compute range */
-        if(chunks.length == 0) {
+        if(chunks.size() == 0) {
             this.x_min = 0;
             this.x_max = 0;
             this.z_min = 0;
@@ -217,24 +215,32 @@ public class NewMapChunkCache implements MapChunkCache {
             x_dim = 1;            
         }
         else {
-            x_min = x_max = chunks[0].x;
+            x_min = x_max = chunks.get(0).x;
-            z_min = z_max = chunks[0].z;
+            z_min = z_max = chunks.get(0).z;
-            for(int i = 1; i < chunks.length; i++) {
+            for(DynmapChunk c : chunks) {
-                if(chunks[i].x > x_max)
+                if(c.x > x_max)
-                    x_max = chunks[i].x;
+                    x_max = c.x;
-                if(chunks[i].x < x_min)
+                if(c.x < x_min)
-                    x_min = chunks[i].x;
+                    x_min = c.x;
-                if(chunks[i].z > z_max)
+                if(c.z > z_max)
-                    z_max = chunks[i].z;
+                    z_max = c.z;
-                if(chunks[i].z < z_min)
+                if(c.z < z_min)
-                    z_min = chunks[i].z;
+                    z_min = c.z;
             }
             x_dim = x_max - x_min + 1;            
         }
     
         snaparray = new ChunkSnapshot[x_dim * (z_max-z_min+1)];
+    }
+    
+    public int loadChunks(int max_to_load) {
+        int cnt = 0;
+        if(iterator == null)
+            iterator = chunks.listIterator();
+        
         // Load the required chunks.
-        for (DynmapChunk chunk : chunks) {
+        while((cnt < max_to_load) && iterator.hasNext()) {
+            DynmapChunk chunk = iterator.next();
             boolean vis = true;
             if(visible_limits != null) {
                 vis = false;
@@ -286,13 +292,25 @@ public class NewMapChunkCache implements MapChunkCache {
                     Log.severe("Cannot pop preserved chunk - " + x.toString());
                 }
             }
+            cnt++;
         }
+        if(iterator.hasNext() == false) {   /* If we're done */
             /* Fill missing chunks with empty dummy chunk */
             for(int i = 0; i < snaparray.length; i++) {
                 if(snaparray[i] == null)
                     snaparray[i] = EMPTY;
             }
         }
+        return cnt;
+    }
+    /**
+     * Test if done loading
+     */
+    public boolean isDoneLoading() {
+        if(iterator != null)
+            return !iterator.hasNext();
+        return false;
+    }
     /**
      * Unload chunks
      */