1 files changed, 77 insertions, 0 deletions
diff --git a/patches/server/0140-Do-not-submit-profile-lookups-to-worldgen-threads.patch b/patches/server/0140-Do-not-submit-profile-lookups-to-worldgen-threads.patch
new file mode 100644
index 0000000000..b2385e0d42
--- /dev/null
+++ b/patches/server/0140-Do-not-submit-profile-lookups-to-worldgen-threads.patch
@@ -0,0 +1,77 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Spottedleaf <[email protected]>
+Date: Sun, 8 Aug 2021 16:26:46 -0700
+Subject: [PATCH] Do not submit profile lookups to worldgen threads
+
+They block. On network I/O.
+
+If enough tasks are submitted the server will eventually stall
+out due to a sync load, as the worldgen threads will be
+stalling on profile lookups.
+
+diff --git a/src/main/java/net/minecraft/Util.java b/src/main/java/net/minecraft/Util.java
+index 168ab805ecc48dd55db90eb7fe1c56fda3f2776c..336a26733b5bf73455f8ec10347c1e08b8e866f7 100644
+--- a/src/main/java/net/minecraft/Util.java
++++ b/src/main/java/net/minecraft/Util.java
+@@ -81,6 +81,22 @@ public class Util {
+     private static final AtomicInteger WORKER_COUNT = new AtomicInteger(1);
+     private static final ExecutorService BOOTSTRAP_EXECUTOR = makeExecutor("Bootstrap");
+     private static final ExecutorService BACKGROUND_EXECUTOR = makeExecutor("Main");
++    // Paper start - don't submit BLOCKING PROFILE LOOKUPS to the world gen thread
++    public static final ExecutorService PROFILE_EXECUTOR = Executors.newFixedThreadPool(2, new java.util.concurrent.ThreadFactory() {
++
++        private final AtomicInteger count = new AtomicInteger();
++
++        @Override
++        public Thread newThread(Runnable run) {
++            Thread ret = new Thread(run);
++            ret.setName("Profile Lookup Executor #" + this.count.getAndIncrement());
++            ret.setUncaughtExceptionHandler((Thread thread, Throwable throwable) -> {
++                LOGGER.error("Uncaught exception in thread " + thread.getName(), throwable);
++            });
++            return ret;
++        }
++    });
++    // Paper end - don't submit BLOCKING PROFILE LOOKUPS to the world gen thread
+     private static final ExecutorService IO_POOL = makeIoExecutor();
+     private static final DateTimeFormatter FILENAME_DATE_TIME_FORMATTER = DateTimeFormatter.ofPattern("yyyy-MM-dd_HH.mm.ss", Locale.ROOT);
+     public static TimeSource.NanoTimeSource timeSource = System::nanoTime;
+diff --git a/src/main/java/net/minecraft/server/players/GameProfileCache.java b/src/main/java/net/minecraft/server/players/GameProfileCache.java
+index 376845f5a25a348e76193fac5c047b0ba2fb080f..2a0cf0a8a79c09566c598197fc6f8c447d4bbd72 100644
+--- a/src/main/java/net/minecraft/server/players/GameProfileCache.java
++++ b/src/main/java/net/minecraft/server/players/GameProfileCache.java
+@@ -181,7 +181,7 @@ public class GameProfileCache {
+             } else {
+                 this.requests.put(username, CompletableFuture.supplyAsync(() -> {
+                     return this.get(username);
+-                }, Util.backgroundExecutor()).whenCompleteAsync((optional, throwable) -> {
++                }, Util.PROFILE_EXECUTOR).whenCompleteAsync((optional, throwable) -> { // Paper - not a good idea to use BLOCKING OPERATIONS on the worldgen executor
+                     this.requests.remove(username);
+                 }, this.executor).whenCompleteAsync((optional, throwable) -> {
+                     consumer.accept(optional);
+diff --git a/src/main/java/net/minecraft/world/level/block/entity/SkullBlockEntity.java b/src/main/java/net/minecraft/world/level/block/entity/SkullBlockEntity.java
+index 0c7e29b589ab106013d979a20edc415b4b32a677..c5d5d90d10b30f30d1262367b3d75df43fbdb231 100644
+--- a/src/main/java/net/minecraft/world/level/block/entity/SkullBlockEntity.java
++++ b/src/main/java/net/minecraft/world/level/block/entity/SkullBlockEntity.java
+@@ -120,7 +120,7 @@ public class SkullBlockEntity extends BlockEntity {
+     public static void updateGameprofile(@Nullable GameProfile owner, Consumer<GameProfile> callback) {
+         if (owner != null && !StringUtil.isNullOrEmpty(owner.getName()) && (!owner.isComplete() || !owner.getProperties().containsKey("textures")) && profileCache != null && sessionService != null) {
+             profileCache.getAsync(owner.getName(), (profile) -> {
+-                Util.backgroundExecutor().execute(() -> {
++                Util.PROFILE_EXECUTOR.execute(() -> { // Paper - not a good idea to use BLOCKING OPERATIONS on the worldgen executor
+                     Util.ifElse(profile, (profilex) -> {
+                         Property property = Iterables.getFirst(profilex.getProperties().get("textures"), (Property)null);
+                         if (property == null) {
+diff --git a/src/main/java/org/bukkit/craftbukkit/profile/CraftPlayerProfile.java b/src/main/java/org/bukkit/craftbukkit/profile/CraftPlayerProfile.java
+index 2d49bd6f3f017d43dfaa23cedf35040b64bcdcf8..9edc5e73819e0b55372f77c5e292eece74d837c7 100644
+--- a/src/main/java/org/bukkit/craftbukkit/profile/CraftPlayerProfile.java
++++ b/src/main/java/org/bukkit/craftbukkit/profile/CraftPlayerProfile.java
+@@ -121,7 +121,7 @@ public final class CraftPlayerProfile implements PlayerProfile {
+ 
+     @Override
+     public CompletableFuture<PlayerProfile> update() {
+-        return CompletableFuture.supplyAsync(this::getUpdatedProfile, Util.backgroundExecutor());
++        return CompletableFuture.supplyAsync(this::getUpdatedProfile, Util.PROFILE_EXECUTOR); // Paper - not a good idea to use BLOCKING OPERATIONS on the worldgen executor
+     }
+ 
+     private CraftPlayerProfile getUpdatedProfile() {