From a4161bf83b718e0ae8b6bfe8689d36ad6faba27e Mon Sep 17 00:00:00 2001 From: Aikar Date: Fri, 4 Mar 2016 18:18:37 -0600 Subject: [PATCH] Chunk save queue improvements For some unknown reason, Minecraft is sleeping 10ms between every single chunk being saved to disk. Under high chunk load/unload activity (lots of movement / teleporting), this causes the chunk unload queue to build up in size. This has multiple impacts: 1) Performance of the unload queue itself - The save thread is pretty ineffecient for how it accesses it By letting the queue get larger, checking and popping work off the queue can get less performant. 2) Performance of chunk loading - As with #1, chunk loads also have to check this queue when loading chunk data so that it doesn't load stale data if new data is pending write to disk. 3) Memory Usage - The entire chunk has been serialized to NBT, and now sits in this queue. This leads to elevated memory usage, and then the objects used in the serialization sit around longer than needed, resulting in promotion to Old Generation instead of dying young. To optimize this, we change the entire unload queue to be a proper queue. This improves the behavior of popping the first queued chunk off, instead of abusing iterators like Mojang was doing. This also improves reliability of chunk saving, as the previous hack job had a race condition that could fail to save some chunks. Then finally, Sleeping will by default be removed, but due to known issues with 1.9, a config option was added. But if sleeps are to remain enabled, we at least lower the sleep interval so it doesn't have as much negative impact. diff --git a/src/main/java/com/destroystokyo/paper/PaperConfig.java b/src/main/java/com/destroystokyo/paper/PaperConfig.java index 259e3b7..c1a8243 100644 --- a/src/main/java/com/destroystokyo/paper/PaperConfig.java +++ b/src/main/java/com/destroystokyo/paper/PaperConfig.java @@ -189,4 +189,10 @@ public class PaperConfig { private static void chunkLoadThreads() { minChunkLoadThreads = Math.min(6, getInt("settings.min-chunk-load-threads", 2)); // Keep people from doing stupid things with max of 6 } + + public static boolean enableFileIOThreadSleep; + private static void enableFileIOThreadSleep() { + enableFileIOThreadSleep = getBoolean("settings.sleep-between-chunk-saves", false); + if (enableFileIOThreadSleep) Bukkit.getLogger().info("Enabled sleeping between chunk saves, beware of memory issues"); + } } diff --git a/src/main/java/net/minecraft/server/ChunkRegionLoader.java b/src/main/java/net/minecraft/server/ChunkRegionLoader.java index 162cdd6..e6e7626 100644 --- a/src/main/java/net/minecraft/server/ChunkRegionLoader.java +++ b/src/main/java/net/minecraft/server/ChunkRegionLoader.java @@ -12,14 +12,17 @@ import java.util.Map; import java.util.Set; import java.util.concurrent.ConcurrentHashMap; import javax.annotation.Nullable; +import java.util.concurrent.ConcurrentLinkedQueue; // Paper import org.apache.logging.log4j.LogManager; import org.apache.logging.log4j.Logger; public class ChunkRegionLoader implements IChunkLoader, IAsyncChunkSaver { + private ConcurrentLinkedQueue queue = new ConcurrentLinkedQueue<>(); // Paper - Chunk queue improvements + private final Object lock = new Object(); // Paper - Chunk queue improvements private static final Logger a = LogManager.getLogger(); private final Map b = new ConcurrentHashMap(); - private final Set c = Collections.newSetFromMap(new ConcurrentHashMap()); + //private final Set c = Collections.newSetFromMap(new ConcurrentHashMap()); // Paper - Chunk queue improvements private final File d; private final DataConverterManager e; private boolean f; @@ -33,11 +36,11 @@ public class ChunkRegionLoader implements IChunkLoader, IAsyncChunkSaver { public boolean chunkExists(World world, int i, int j) { ChunkCoordIntPair chunkcoordintpair = new ChunkCoordIntPair(i, j); - if (this.c.contains(chunkcoordintpair)) { + //if (this.c.contains(chunkcoordintpair)) { // Paper - Chunk queue improvements if (this.b.containsKey(chunkcoordintpair)) { return true; } - } + //} // Paper - Chunk queue improvements // Paper start - Don't create region files when checking that they exist final RegionFile region = RegionFileCache.a(this.d, i, j, false); @@ -143,35 +146,32 @@ public class ChunkRegionLoader implements IChunkLoader, IAsyncChunkSaver { } protected void a(ChunkCoordIntPair chunkcoordintpair, NBTTagCompound nbttagcompound) { - if (!this.c.contains(chunkcoordintpair)) { + synchronized (lock) { // Paper - Chunk queue improvements this.b.put(chunkcoordintpair, nbttagcompound); } + queue.add(new QueuedChunk(chunkcoordintpair, nbttagcompound)); // Paper - Chunk queue improvements FileIOThread.a().a(this); } public boolean c() { - // CraftBukkit start - Iterator> iter = this.b.entrySet().iterator(); - if (!iter.hasNext()) { - // CraftBukkit end + // Paper start - Chunk queue improvements + QueuedChunk chunk = queue.poll(); + if (chunk == null) { + // Paper - end if (this.f) { ChunkRegionLoader.a.info("ThreadedAnvilChunkStorage ({}): All chunks are saved", new Object[] { this.d.getName()}); } return false; } else { - // CraftBukkit start - Map.Entry entry = iter.next(); - iter.remove(); // Pop single entry - ChunkCoordIntPair chunkcoordintpair = entry.getKey(); - // CraftBukkit end + ChunkCoordIntPair chunkcoordintpair = chunk.coords; // Paper - Chunk queue improvements boolean flag; try { - this.c.add(chunkcoordintpair); - NBTTagCompound nbttagcompound = (NBTTagCompound) entry.getValue(); // CraftBukkit + //this.c.add(chunkcoordintpair); + NBTTagCompound nbttagcompound = chunk.compound; // Paper - Chunk queue improvements if (nbttagcompound != null) { try { @@ -180,10 +180,11 @@ public class ChunkRegionLoader implements IChunkLoader, IAsyncChunkSaver { ChunkRegionLoader.a.error("Failed to save chunk", exception); } } + synchronized (lock) { if (this.b.get(chunkcoordintpair) == nbttagcompound) { this.b.remove(chunkcoordintpair); } }// Paper - This will not equal if a newer version is still pending flag = true; } finally { - this.c.remove(chunkcoordintpair); + //this.c.remove(chunkcoordintpair); // Paper } return flag; @@ -554,4 +555,16 @@ public class ChunkRegionLoader implements IChunkLoader, IAsyncChunkSaver { return entity; } } + + // Paper start - Chunk queue improvements + private static class QueuedChunk { + public ChunkCoordIntPair coords; + public NBTTagCompound compound; + + public QueuedChunk(ChunkCoordIntPair coords, NBTTagCompound compound) { + this.coords = coords; + this.compound = compound; + } + } + // Paper end } diff --git a/src/main/java/net/minecraft/server/FileIOThread.java b/src/main/java/net/minecraft/server/FileIOThread.java index acfdd52..fdbaf5f 100644 --- a/src/main/java/net/minecraft/server/FileIOThread.java +++ b/src/main/java/net/minecraft/server/FileIOThread.java @@ -39,11 +39,15 @@ public class FileIOThread implements Runnable { ++this.d; } - try { - Thread.sleep(this.e ? 0L : 10L); - } catch (InterruptedException interruptedexception) { - interruptedexception.printStackTrace(); + // Paper start - Add toggle + if (com.destroystokyo.paper.PaperConfig.enableFileIOThreadSleep) { + try { + Thread.sleep(this.e ? 0L : 2L); + } catch (InterruptedException interruptedexception) { + interruptedexception.printStackTrace(); + } } + // Paper end } if (this.b.isEmpty()) { -- 2.9.3