fix JFR GC events

Author: roberttoyonaga

substratevm/src/com.oracle.svm.core.genscavenge/src/com/oracle/svm/core/genscavenge/JfrGCEventSupport.java

@@ -75,6 +75,7 @@ public void emitGarbageCollectionEvent(UnsignedWord gcEpoch, GCCause cause, long
             JfrNativeEventWriter.beginSmallEvent(data, JfrEvent.GarbageCollection);
             JfrNativeEventWriter.putLong(data, startTicks);
             JfrNativeEventWriter.putLong(data, duration);
+            JfrNativeEventWriter.putEventThread(data);
             JfrNativeEventWriter.putLong(data, gcEpoch.rawValue());
             JfrNativeEventWriter.putLong(data, gcName.getId());
             JfrNativeEventWriter.putLong(data, cause.getId());

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

@@ -0,0 +1,69 @@
+/*
+ * Copyright (c) 2022, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2022, 2022, 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 com.oracle.svm.core.jfr.JfrEvent;
+import jdk.jfr.Recording;
+import jdk.jfr.consumer.RecordedEvent;
+import jdk.jfr.consumer.RecordedThread;
+import org.junit.Test;
+
+import java.util.List;
+
+import static org.junit.Assert.assertTrue;
+
+public class TestGarbageCollectionEvents extends JfrRecordingTest {
+    @Test
+    public void test() throws Throwable {
+        String[] events = new String[]{JfrEvent.GarbageCollection.getName()};
+        Recording recording = startRecording(events);
+        System.gc();
+        System.gc();
+        System.gc();
+        stopRecording(recording, TestGarbageCollectionEvents::validateEvents);
+    }
+
+    private static void validateEvents(List<RecordedEvent> events) {
+        assertTrue(events.size() > 0);
+        int foundSystemGc = 0;
+        int expectedId = 0;
+        for (RecordedEvent event : events) {
+            assertTrue(expectedId == event.getInt("gcId"));
+            assertTrue(event.getThread("eventThread").getJavaName() != null);
+            assertTrue(!event.getDuration().isZero());
+            assertTrue(event.getString("name") != null);
+            assertTrue(event.getLong("longestPause") > 0);
+            assertTrue(event.getLong("sumOfPauses") > 0);
+            if (event.getString("cause").equals("java.lang.System.gc()")) {
+                foundSystemGc++;
+            }
+            expectedId++;
+        }
+        assertTrue(foundSystemGc >= 3);
+        assertTrue(expectedId >= 3);
+    }
+}