1 /*
 2  * Copyright (c) 2015, 2025, Oracle and/or its affiliates. All rights reserved.
 3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 4  *
 5  * This code is free software; you can redistribute it and/or modify it
 6  * under the terms of the GNU General Public License version 2 only, as
 7  * published by the Free Software Foundation.
 8  *
 9  * This code is distributed in the hope that it will be useful, but WITHOUT
10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
12  * version 2 for more details (a copy is included in the LICENSE file that
13  * accompanied this code).
14  *
15  * You should have received a copy of the GNU General Public License version
16  * 2 along with this work; if not, write to the Free Software Foundation,
17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18  *
19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20  * or visit www.oracle.com if you need additional information or have any
21  * questions.
22  */
23 package jdk.jfr.event.oldobject;
24 
25 import java.io.IOException;
26 import java.nio.file.Path;
27 import java.nio.file.Paths;
28 import java.util.ArrayList;
29 import java.util.List;
30 
31 import jdk.jfr.Recording;
32 import jdk.jfr.consumer.RecordedEvent;
33 import jdk.jfr.consumer.RecordingFile;
34 import jdk.jfr.internal.test.WhiteBox;
35 import jdk.test.lib.jfr.EventNames;
36 import jdk.test.lib.jfr.Events;
37 
38 /**
39  * @test
40  * @requires vm.flagless
41  * @requires vm.hasJFR
42  * @library /test/lib /test/jdk
43  * @modules jdk.jfr/jdk.jfr.internal.test
44  * @run main/othervm -XX:TLABSize=2k jdk.jfr.event.oldobject.TestLastKnownHeapUsage
45  */
46 public class TestLastKnownHeapUsage {
47 
48     public final static List<Object> heap = new ArrayList<>();
49 
50     public static void main(String[] args) throws Exception {
51         WhiteBox.setWriteAllObjectSamples(true);
52         long last = 0;
53         for (int i = 1; i <= 5; i++) {
54             long heapUsage = recordOldObjects(i);
55             System.out.println("Recording: " + i + " heapUsage=" + heapUsage);
56             if (heapUsage < last) {
57                 throw new Exception("Unexpect decrease of heap usage");
58             }
59         }
60     }
61 
62     private static long recordOldObjects(int index) throws IOException {
63         try (Recording r = new Recording()) {
64             r.enable(EventNames.OldObjectSample).withStackTrace().with("cutoff", "infinity");
65             r.start();
66             System.gc();
67             for (int i = 0; i < 20; i++) {
68                 heap.add(new byte[1_000_000]);
69             }
70             System.gc();
71             r.stop();
72             Path p = Paths.get("recording-" + index + ".jfr");
73             r.dump(p);
74             List<RecordedEvent> events = RecordingFile.readAllEvents(p);
75             Events.hasEvents(events);
76             long max = 0;
77             for (RecordedEvent e : RecordingFile.readAllEvents(p)) {
78                 long heapUsage = Events.assertField(e, "lastKnownHeapUsage").atLeast(0L).below(1_000_000_000L).getValue();
79                 max = Math.max(max, heapUsage);
80             }
81             return max;
82         }
83     }
84 }