PaperMC/paper-server/patches/sources/net/minecraft/util/TickThrottler.java.patch

--- a/net/minecraft/util/TickThrottler.java
+++ b/net/minecraft/util/TickThrottler.java
@@ -3,7 +_,7 @@
 public class TickThrottler {
     private final int incrementStep;
     private final int threshold;
-    private int count;
+    private final java.util.concurrent.atomic.AtomicInteger count = new java.util.concurrent.atomic.AtomicInteger(); // CraftBukkit - multithreaded field
 
     public TickThrottler(int incrementStep, int threshold) {
         this.incrementStep = incrementStep;
@@ -11,16 +_,31 @@
     }
 
     public void increment() {
-        this.count = this.count + this.incrementStep;
+        this.count.addAndGet(this.incrementStep); // CraftBukkit - use thread-safe field access instead
     }
 
     public void tick() {
+        // CraftBukkit start
+        for (int val; (val = this.count.get()) > 0 && !this.count.compareAndSet(val, val - 1); ) ;
+        /* Use thread-safe field access instead
         if (this.count > 0) {
             this.count--;
         }
+        */
+        // CraftBukkit end
     }
 
     public boolean isUnderThreshold() {
-        return this.count < this.threshold;
+        // CraftBukkit start - use thread-safe field access instead
+        return this.count.get() < this.threshold;
+    }
+
+    public boolean isIncrementAndUnderThreshold() {
+        return this.isIncrementAndUnderThreshold(this.incrementStep, this.threshold);
+    }
+
+    public boolean isIncrementAndUnderThreshold(int incrementStep, int threshold) {
+        return this.count.addAndGet(incrementStep) < threshold;
+        // CraftBukkit end
     }
 }