1 files changed, 52 insertions, 0 deletions
diff --git a/patches/server/0747-Consolidate-flush-calls-for-entity-tracker-packets.patch b/patches/server/0747-Consolidate-flush-calls-for-entity-tracker-packets.patch
new file mode 100644
index 0000000000..5b23522f42
--- /dev/null
+++ b/patches/server/0747-Consolidate-flush-calls-for-entity-tracker-packets.patch
@@ -0,0 +1,52 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Spottedleaf <[email protected]>
+Date: Sat, 4 Apr 2020 17:00:20 -0700
+Subject: [PATCH] Consolidate flush calls for entity tracker packets
+
+Most server packets seem to be sent from here, so try to avoid
+expensive flush calls from them.
+
+This change was motivated due to local testing:
+
+- My server spawn has 130 cows in it (for testing a prev. patch)
+- Try to let 200 players join spawn
+
+Without this change, I could only get 20 players on before they
+all started timing out due to the load put on the Netty I/O threads.
+
+With this change I could get all 200 on at 0ms ping.
+
+(one of the primary issues is that my CPU is kinda trash, and having
+4 extra threads at 100% is just too much for it).
+
+So in general this patch should reduce Netty I/O thread load.
+
+diff --git a/src/main/java/net/minecraft/server/level/ServerChunkCache.java b/src/main/java/net/minecraft/server/level/ServerChunkCache.java
+index 98e279e5330b45d0587d1afebddaf876e9802e33..4c82f17313e18c9dfd9b28653715b8a3242b826c 100644
+--- a/src/main/java/net/minecraft/server/level/ServerChunkCache.java
++++ b/src/main/java/net/minecraft/server/level/ServerChunkCache.java
+@@ -893,7 +893,24 @@ public class ServerChunkCache extends ChunkSource {
+             this.level.timings.broadcastChunkUpdates.stopTiming(); // Paper - timing
+             gameprofilerfiller.pop();
+             // Paper end - use set of chunks requiring updates, rather than iterating every single one loaded
++            // Paper start - controlled flush for entity tracker packets
++            List<net.minecraft.network.Connection> disabledFlushes = new java.util.ArrayList<>(this.level.players.size());
++            for (ServerPlayer player : this.level.players) {
++                net.minecraft.server.network.ServerGamePacketListenerImpl connection = player.connection;
++                if (connection != null) {
++                    connection.connection.disableAutomaticFlush();
++                    disabledFlushes.add(connection.connection);
++                }
++            }
++            try { // Paper end - controlled flush for entity tracker packets
+             this.chunkMap.tick();
++            // Paper start - controlled flush for entity tracker packets
++            } finally {
++                for (net.minecraft.network.Connection networkManager : disabledFlushes) {
++                    networkManager.enableAutomaticFlush();
++                }
++            }
++            // Paper end - controlled flush for entity tracker packets
+         }
+     }
+