8351187: Add JFR monitor notification event

Reviewed-by: dholmes, lmesnik, mgronlun

Author: shipilev

src/jdk.jfr/share/conf/jfr/default.jfc

@@ -95,6 +95,12 @@
       <setting name="threshold" control="locking-threshold">20 ms</setting>
     </event>
 
+    <event name="jdk.JavaMonitorNotify">
+      <setting name="enabled">false</setting>
+      <setting name="stackTrace">true</setting>
+      <setting name="threshold">0 ms</setting>
+    </event>
+
     <event name="jdk.JavaMonitorInflate">
       <setting name="enabled">false</setting>
       <setting name="stackTrace">true</setting>

src/jdk.jfr/share/conf/jfr/profile.jfc

@@ -95,6 +95,12 @@
       <setting name="threshold" control="locking-threshold">10 ms</setting>
     </event>
 
+    <event name="jdk.JavaMonitorNotify">
+      <setting name="enabled">false</setting>
+      <setting name="stackTrace">true</setting>
+      <setting name="threshold">0 ms</setting>
+    </event>
+
     <event name="jdk.JavaMonitorInflate">
       <setting name="enabled">false</setting>
       <setting name="stackTrace">true</setting>

test/jdk/jdk/jfr/event/runtime/TestJavaMonitorNotifyEvent.java

@@ -0,0 +1,110 @@
+/*
+ * Copyright (c) 2013, 2025, Oracle and/or its affiliates. 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.
+ *
+ * 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 jdk.jfr.event.runtime;
+
+import static jdk.test.lib.Asserts.assertFalse;
+import static jdk.test.lib.Asserts.assertTrue;
+
+import java.time.Duration;
+import java.util.List;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.CopyOnWriteArrayList;
+
+import jdk.jfr.Recording;
+import jdk.jfr.consumer.RecordingStream;
+import jdk.jfr.consumer.RecordedClass;
+import jdk.jfr.consumer.RecordedEvent;
+import jdk.test.lib.jfr.EventNames;
+import jdk.test.lib.jfr.Events;
+import jdk.test.lib.thread.TestThread;
+import jdk.test.lib.thread.XRun;
+
+/**
+ * @test
+ * @requires vm.flagless
+ * @requires vm.hasJFR
+ * @library /test/lib
+ * @run main/othervm jdk.jfr.event.runtime.TestJavaMonitorNotifyEvent
+ */
+public class TestJavaMonitorNotifyEvent {
+
+    private static final String FIELD_KLASS_NAME = "monitorClass.name";
+    private static final String FIELD_ADDRESS    = "address";
+    private static final String FIELD_NOTIFIED_COUNT = "notifiedCount";
+
+    private final static String EVENT_NAME = EventNames.JavaMonitorNotify;
+    private static final long WAIT_TIME = 123456;
+
+    static class Lock {
+    }
+
+    public static void main(String[] args) throws Throwable {
+        final Lock lock = new Lock();
+        final String lockClassName = lock.getClass().getName().replace('.', '/');
+        final long mainThreadId = Thread.currentThread().threadId();
+
+        List<RecordedEvent> events = new CopyOnWriteArrayList<>();
+        try (RecordingStream rs = new RecordingStream()) {
+            rs.enable(EVENT_NAME).withoutThreshold();
+            rs.onEvent(EVENT_NAME, e -> {
+                long threadId = e.getThread().getJavaThreadId();
+                Object clazz = e.getValue(FIELD_KLASS_NAME);
+                if (clazz.equals(lockClassName) && (threadId == mainThreadId)) {
+                    events.add(e);
+                    rs.close();
+                }
+            });
+            rs.startAsync();
+
+            final CountDownLatch latch = new CountDownLatch(1);
+            TestThread waitThread = new TestThread(new XRun() {
+                @Override
+                public void xrun() throws Throwable {
+                    synchronized (lock) {
+                        latch.countDown();
+                        lock.wait(WAIT_TIME);
+                    }
+                }
+            });
+            try {
+                waitThread.start();
+                latch.await();
+                synchronized (lock) {
+                    lock.notifyAll();
+                }
+            } finally {
+                waitThread.join();
+            }
+
+            rs.awaitTermination();
+
+            System.out.println(events);
+            assertFalse(events.isEmpty());
+            for (RecordedEvent ev : events) {
+                Events.assertField(ev, FIELD_ADDRESS).notEqual(0L);
+                Events.assertField(ev, FIELD_NOTIFIED_COUNT).equal(1);
+            }
+        }
+    }
+}

test/lib/jdk/test/lib/jfr/EventNames.java

@@ -58,6 +58,7 @@ public class EventNames {
     public static final String ThreadPark = PREFIX + "ThreadPark";
     public static final String JavaMonitorEnter = PREFIX + "JavaMonitorEnter";
     public static final String JavaMonitorWait = PREFIX + "JavaMonitorWait";
+    public static final String JavaMonitorNotify = PREFIX + "JavaMonitorNotify";
     public static final String JavaMonitorInflate = PREFIX + "JavaMonitorInflate";
     public static final String JavaMonitorDeflate = PREFIX + "JavaMonitorDeflate";
     public static final String JavaMonitorStatistics = PREFIX + "JavaMonitorStatistics";