Reduce lock contention in Thread.getAndClearInterrupt

Lock contention in Thread.getAndClearInterrupt is reduced by acquiring the lock only when the value of the Thread.interrupted field is true. Related: eclipse-openj9/openj9#20414 Signed-off-by: Babneet Singh <[email protected]>
ibmruntimes · Oct 28, 2024 · dd35ec6 · dd35ec6
1 parent 006fde1
commit dd35ec6
Showing 1 changed file with 9 additions and 6 deletions.
diff --git a/src/java.base/share/classes/java/lang/Thread.java b/src/java.base/share/classes/java/lang/Thread.java
@@ -1805,14 +1805,17 @@ boolean getAndClearInterrupt() {
         if (com.ibm.oti.vm.VM.isJVMInSingleThreadedMode()) {
             return interruptedImpl();
         }
-        synchronized (interruptLock) {
-            boolean oldValue = interrupted;
-            if (oldValue) {
-                interrupted = false;
-                clearInterruptEvent();
+        boolean oldValue = interrupted;
+        if (oldValue) {
+            synchronized (interruptLock) {
+                oldValue = interrupted;
+                if (oldValue) {
+                    interrupted = false;
+                    clearInterruptEvent();
+                }
             }
-            return oldValue;
         }
+        return oldValue;
     }
 
     /**