[GR-69121] Skip emission of internal JFR ThreadPark events.

substratevm/src/com.oracle.svm.core/src/com/oracle/svm/core/jfr/events/ThreadParkEvent.java

@@ -1,6 +1,6 @@
 /*
- * Copyright (c) 2022, 2022, Oracle and/or its affiliates. All rights reserved.
- * Copyright (c) 2022, 2022, Red Hat Inc. All rights reserved.
+ * Copyright (c) 2022, 2025, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2022, 2025, Red Hat Inc. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -26,7 +26,6 @@
 
 package com.oracle.svm.core.jfr.events;
 
-import jdk.graal.compiler.word.Word;
 import org.graalvm.nativeimage.StackValue;
 
 import com.oracle.svm.core.Uninterruptible;
@@ -37,10 +36,13 @@
 import com.oracle.svm.core.jfr.JfrNativeEventWriterDataAccess;
 import com.oracle.svm.core.jfr.JfrTicks;
 import com.oracle.svm.core.jfr.SubstrateJVM;
+import com.oracle.svm.core.monitor.JavaMonitorQueuedSynchronizer;
+
+import jdk.graal.compiler.word.Word;
 
 public class ThreadParkEvent {
     public static void emit(long startTicks, Object obj, boolean isAbsolute, long time) {
-        if (HasJfrSupport.get()) {
+        if (HasJfrSupport.get() && !isInternalPark(obj)) {
             emit0(startTicks, obj, isAbsolute, time);
         }
     }
@@ -76,4 +78,22 @@ private static void emit0(long startTicks, Object obj, boolean isAbsolute, long
             JfrNativeEventWriter.endSmallEvent(data);
         }
     }
+
+    /**
+     * Skip emission if this is an internal park ({@link JavaMonitorWaitEvent} or
+     * {@link JavaMonitorEnterEvent} will be emitted instead).
+     */
+    private static boolean isInternalPark(Object obj) {
+        if (obj == null) {
+            return false;
+        }
+
+        Class<?> parkedClass = obj.getClass();
+        if (JavaMonitorQueuedSynchronizer.class.isAssignableFrom(parkedClass)) {
+            return true;
+        }
+
+        Class<?> enclosingClass = parkedClass.getEnclosingClass();
+        return enclosingClass != null && JavaMonitorQueuedSynchronizer.class.isAssignableFrom(enclosingClass);
+    }
 }

substratevm/src/com.oracle.svm.core/src/com/oracle/svm/core/monitor/JavaMonitorQueuedSynchronizer.java

@@ -60,7 +60,7 @@
  * </ul>
  */
 @BasedOnJDKClass(AbstractQueuedLongSynchronizer.class)
-abstract class JavaMonitorQueuedSynchronizer {
+public abstract class JavaMonitorQueuedSynchronizer {
     // Node status bits, also used as argument and return values
     static final int WAITING = 1; // must be 1
     static final int CANCELLED = 0x80000000; // must be negative

substratevm/src/com.oracle.svm.test/src/com/oracle/svm/test/jfr/TestJavaMonitorEnterEvent.java

@@ -53,25 +53,24 @@ public void test() throws Throwable {
         String[] events = new String[]{JfrEvent.JavaMonitorEnter.getName()};
         Recording recording = startRecording(events);
 
-        Runnable first = () -> {
+        firstThread = new Thread(() -> {
             try {
                 helper.doWork();
             } catch (InterruptedException e) {
                 throw new RuntimeException(e);
             }
-        };
+        });
 
-        Runnable second = () -> {
+        secondThread = new Thread(() -> {
             try {
                 passedCheckpoint = true;
                 helper.doWork();
             } catch (InterruptedException e) {
                 throw new RuntimeException(e);
             }
-        };
-        firstThread = new Thread(first);
-        secondThread = new Thread(second);
+        });
 
+        /* Start the first thread so that it can then start the second thread. */
         firstThread.start();
 
         firstThread.join();

substratevm/src/com.oracle.svm.test/src/com/oracle/svm/test/jfr/TestJavaMonitorInflateEvent.java

@@ -73,7 +73,7 @@ private void test(Object obj) throws Throwable {
     }
 
     private void test(Object obj, String className) throws Throwable {
-        Runnable first = () -> {
+        firstThread = new Thread(() -> {
             try {
                 synchronized (obj) {
                     secondThread.start();
@@ -85,25 +85,25 @@ private void test(Object obj, String className) throws Throwable {
             } catch (InterruptedException e) {
                 throw new RuntimeException(e);
             }
-        };
+        });
 
-        Runnable second = () -> {
+        secondThread = new Thread(() -> {
             passedCheckpoint = true;
             synchronized (obj) {
                 GraalDirectives.blackhole(obj);
             }
-        };
+        });
 
         expectedClassName = className;
-        passedCheckpoint = false;
-        firstThread = new Thread(first);
-        secondThread = new Thread(second);
 
         /* Now that the data is prepared, start the JFR recording. */
         String[] events = new String[]{JfrEvent.JavaMonitorInflate.getName()};
         Recording recording = startRecording(events);
 
-        /* Generate event with "Monitor Enter" cause. */
+        /*
+         * Generate event with "Monitor Enter" cause. Start the first thread so that it can then
+         * start the second thread.
+         */
         firstThread.start();
 
         firstThread.join();

substratevm/src/com.oracle.svm.test/src/com/oracle/svm/test/jfr/TestOmitInternalParkEvents.java

@@ -0,0 +1,129 @@
+/*
+ * Copyright (c) 2022, 2025, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2022, 2025, Red Hat Inc. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+package com.oracle.svm.test.jfr;
+
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+import static org.junit.Assert.fail;
+
+import java.util.List;
+import java.util.concurrent.locks.LockSupport;
+
+import org.junit.Test;
+
+import com.oracle.svm.core.jfr.JfrEvent;
+import com.oracle.svm.core.util.TimeUtils;
+
+import jdk.jfr.Recording;
+import jdk.jfr.consumer.RecordedClass;
+import jdk.jfr.consumer.RecordedEvent;
+
+public class TestOmitInternalParkEvents extends JfrRecordingTest {
+    private static final int MILLIS = 100;
+    private final MonitorHelper monitorHelper = new MonitorHelper();
+    private Thread secondThread;
+    private volatile boolean passedCheckpoint;
+
+    @Test
+    public void test() throws Throwable {
+        String[] events = new String[]{JfrEvent.JavaMonitorEnter.getName(), JfrEvent.JavaMonitorWait.getName(), JfrEvent.ThreadPark.getName()};
+        Recording recording = startRecording(events);
+
+        /* Generate monitor enter events. */
+        Thread firstThread = new Thread(() -> {
+            try {
+                monitorHelper.doWork();
+            } catch (InterruptedException e) {
+                throw new RuntimeException(e);
+            }
+        });
+
+        secondThread = new Thread(() -> {
+            try {
+                passedCheckpoint = true;
+                monitorHelper.doWork();
+            } catch (InterruptedException e) {
+                throw new RuntimeException(e);
+            }
+        });
+
+        /* Start the first thread so that it can then start the second thread. */
+        firstThread.start();
+
+        firstThread.join();
+        secondThread.join();
+
+        /* Generate monitor wait events. */
+        try {
+            monitorHelper.waitUntilTimeout();
+        } catch (InterruptedException e) {
+            fail(e.getMessage());
+        }
+
+        /* Generate thread park events. */
+        LockSupport.parkNanos(this, TimeUtils.millisToNanos(MILLIS));
+
+        stopRecording(recording, this::validateEvents);
+    }
+
+    private void validateEvents(List<RecordedEvent> events) {
+        boolean found = false;
+        for (RecordedEvent event : events) {
+            if (event.getEventType().getName().equals(JfrEvent.ThreadPark.getName())) {
+                RecordedClass parkedClass = event.getValue("parkedClass");
+                if (parkedClass != null) {
+                    String parkedClassName = parkedClass.getName();
+                    assertFalse(parkedClassName.contains("JavaMonitor"));
+                    found = true;
+                }
+            }
+        }
+        assertTrue("Expected jdk.ThreadPark event not found", found);
+    }
+
+    private final class MonitorHelper {
+        private synchronized void doWork() throws InterruptedException {
+            if (Thread.currentThread().equals(secondThread)) {
+                /* The second thread doesn't need to do any work. */
+                return;
+            }
+
+            /* Start the second thread while this thread holds the lock. */
+            secondThread.start();
+
+            /* Spin until the second thread blocks. */
+            while (!secondThread.getState().equals(Thread.State.BLOCKED) || !passedCheckpoint) {
+                Thread.sleep(100);
+            }
+            Thread.sleep(MILLIS);
+        }
+
+        private synchronized void waitUntilTimeout() throws InterruptedException {
+            wait(MILLIS);
+        }
+    }
+}