From 7cbce377a70ccc2b972391ea7ef566af71b20d3f Mon Sep 17 00:00:00 2001
From: bea4dev <bea0224@outlook.jp>
Date: Wed, 13 Sep 2023 00:00:28 +0900
Subject: [PATCH] fix Low accuracy tick rate

(cherry picked from commit ce9d254a23791403a2b19ee4bb6bb52e175fa5dd)
(cherry picked from commit 4e33a5e6d8ab55b2bd39db18df66c1659ab4ffbd)
---
 .../minestom/server/ServerProcessImpl.java    |  3 +++
 .../server/network/socket/Server.java         |  4 ++++
 .../server/network/socket/Worker.java         |  7 ++++--
 .../server/thread/TickSchedulerThread.java    | 24 ++++++++++++++++---
 4 files changed, 33 insertions(+), 5 deletions(-)

diff --git a/src/main/java/net/minestom/server/ServerProcessImpl.java b/src/main/java/net/minestom/server/ServerProcessImpl.java
index 176881ccf..694526fb8 100644
--- a/src/main/java/net/minestom/server/ServerProcessImpl.java
+++ b/src/main/java/net/minestom/server/ServerProcessImpl.java
@@ -297,6 +297,9 @@ final class ServerProcessImpl implements ServerProcess {
             // Flush all waiting packets
             PacketUtils.flush();
 
+            // Server connection tick
+            server().tick();
+
             // Monitoring
             {
                 final double acquisitionTimeMs = Acquirable.resetAcquiringTime() / 1e6D;
diff --git a/src/main/java/net/minestom/server/network/socket/Server.java b/src/main/java/net/minestom/server/network/socket/Server.java
index 8d3d6310d..6975a9697 100644
--- a/src/main/java/net/minestom/server/network/socket/Server.java
+++ b/src/main/java/net/minestom/server/network/socket/Server.java
@@ -91,6 +91,10 @@ public final class Server {
         }, "Ms-entrypoint").start();
     }
 
+    public void tick() {
+        this.workers.forEach(Worker::tick);
+    }
+
     public boolean isOpen() {
         return !stop;
     }
diff --git a/src/main/java/net/minestom/server/network/socket/Worker.java b/src/main/java/net/minestom/server/network/socket/Worker.java
index 6da7723ac..217e0d331 100644
--- a/src/main/java/net/minestom/server/network/socket/Worker.java
+++ b/src/main/java/net/minestom/server/network/socket/Worker.java
@@ -39,6 +39,10 @@ public final class Worker extends MinestomThread {
         }
     }
 
+    public void tick() {
+        this.selector.wakeup();
+    }
+
     @Override
     public void run() {
         while (server.isOpen()) {
@@ -86,7 +90,7 @@ public final class Worker extends MinestomThread {
                         MinecraftServer.getExceptionManager().handleException(t);
                         connection.disconnect();
                     }
-                }, MinecraftServer.TICK_MS);
+                });
             } catch (Exception e) {
                 MinecraftServer.getExceptionManager().handleException(e);
             }
@@ -118,7 +122,6 @@ public final class Worker extends MinestomThread {
             socket.setTcpNoDelay(Server.NO_DELAY);
             socket.setSoTimeout(30 * 1000); // 30 seconds
         }
-        this.selector.wakeup();
     }
 
     public MessagePassingQueue<Runnable> queue() {
diff --git a/src/main/java/net/minestom/server/thread/TickSchedulerThread.java b/src/main/java/net/minestom/server/thread/TickSchedulerThread.java
index fcf60b76d..3a9c57451 100644
--- a/src/main/java/net/minestom/server/thread/TickSchedulerThread.java
+++ b/src/main/java/net/minestom/server/thread/TickSchedulerThread.java
@@ -25,9 +25,27 @@ public final class TickSchedulerThread extends MinestomThread {
             } catch (Exception e) {
                 serverProcess.exception().handleException(e);
             }
-            final long wait = tickStart + tickNs - System.nanoTime();
-            assert wait <= tickNs : "Wait time is too long: " + (wait / 1e6) + "ms";
-            LockSupport.parkNanos(wait);
+            fixTickRate(tickNs);
         }
     }
+
+
+    private final long startTickNs = System.nanoTime();
+    private long tick = 1;
+
+    private void fixTickRate(long tickNs) {
+        long nextTickNs = startTickNs + (tickNs * tick);
+        if (System.nanoTime() < nextTickNs) {
+            while (true) {
+                // Checks in every 1/10 ms to see if the current time has reached the next scheduled time.
+                Thread.yield();
+                LockSupport.parkNanos(100000);
+                long currentNs = System.nanoTime();
+                if (currentNs >= nextTickNs) {
+                    break;
+                }
+            }
+        }
+        tick++;
+    }
 }