1 /*
2 * Copyright (c) 2013, 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
24 package jdk.jfr.event.allocation;
25
26 import static java.lang.Math.floor;
27
28 import jdk.jfr.Recording;
29 import jdk.jfr.consumer.RecordedEvent;
30 import jdk.test.lib.jfr.EventNames;
31 import jdk.test.lib.jfr.Events;
32 import jdk.test.lib.Asserts;
33 import jdk.test.lib.Platform;
34 import jdk.test.whitebox.WhiteBox;
35
36 /**
37 * @test
38 * @summary Test that event is triggered when an object is allocated in a new TLAB.
39 * @requires vm.flagless
40 * @requires vm.hasJFR
41 * @library /test/lib
42 * @build jdk.test.whitebox.WhiteBox
43 *
44 * @run driver jdk.test.lib.helpers.ClassFileInstaller jdk.test.whitebox.WhiteBox
45 * @run main/othervm -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI -Xbootclasspath/a:.
46 * -XX:+UseTLAB -XX:TLABSize=100k -XX:-ResizeTLAB -XX:TLABRefillWasteFraction=1
47 * jdk.jfr.event.allocation.TestObjectAllocationInNewTLABEvent
48 * @run main/othervm -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI -Xbootclasspath/a:.
49 * -XX:+UseTLAB -XX:TLABSize=100k -XX:-ResizeTLAB -XX:TLABRefillWasteFraction=1
50 * -Xint
51 * jdk.jfr.event.allocation.TestObjectAllocationInNewTLABEvent
52 */
53
54 /**
55 * Test that when an object is allocated in a new Thread Local Allocation Buffer (TLAB)
56 * an event will be triggered. The test is done for default and interpreted mode (-Xint).
57 *
58 * To force objects to be allocated in a new TLAB:
59 * the initial size of TLAB is set to 100k (-XX:TLABSize=100k);
60 * the size of allocated objects is set to 128k;
61 * max TLAB waste at refill is set to minimum (-XX:TLABRefillWasteFraction=1),
62 * to provoke a new TLAB creation.
63 */
64 public class TestObjectAllocationInNewTLABEvent {
65 private final static String EVENT_NAME = EventNames.ObjectAllocationInNewTLAB;
66
67 private static final Boolean COMPRESSED_CLASS_PTRS = WhiteBox.getWhiteBox().getBooleanVMFlag("UseCompressedClassPointers");
68
69 private static final int BYTE_ARRAY_OVERHEAD = (Platform.is64bit() && !COMPRESSED_CLASS_PTRS) ? 24 : 16;
70 private static final int OBJECT_SIZE = 128 * 1024;
71
72 private static final int OBJECTS_TO_ALLOCATE = 100;
73 private static final String BYTE_ARRAY_CLASS_NAME = new byte[0].getClass().getName();
74 private static final int INITIAL_TLAB_SIZE = 100 * 1024;
75 private static int countAllTlabs; // Count all matching tlab allocations.
76 private static int countFullTlabs; // Count matching tlab allocations with full tlab size.
77
78 // Make sure allocation isn't dead code eliminated.
79 public static byte[] tmp;
80
81 public static void main(String[] args) throws Exception {
82 Recording recording = new Recording();
83 recording.enable(EVENT_NAME);
84 recording.start();
85 System.gc();
86 allocate();
87 recording.stop();
88 verifyRecording(recording);
89 int minCount = (int) floor(OBJECTS_TO_ALLOCATE * 0.80);
90 Asserts.assertGreaterThanOrEqual(countAllTlabs, minCount, "Too few tlab objects allocated");
91 Asserts.assertLessThanOrEqual(countAllTlabs, OBJECTS_TO_ALLOCATE, "Too many tlab objects allocated");
92
93 // For most GCs we expect the size of each tlab to be
94 // INITIAL_TLAB_SIZE + ALLOCATION_SIZE, but that is not always true for G1.
95 // G1 may use a smaller tlab size if the full tlab does not fit in the
96 // selected memory region.
97 //
98 // For example, if a G1 memory region has room for 4.7 tlabs,
99 // then the first 4 tlabs will have the expected size,
100 // but the fifth tlab would only have a size of 0.7*expected.
101 //
102 // It is only the last tlab in each region that has a smaller size.
103 // This means that at least 50% of the allocated tlabs should
104 // have the expected size (1 full tlab, and 1 fractional tlab).
105 Asserts.assertGreaterThanOrEqual(2*countFullTlabs, countAllTlabs, "Too many fractional tlabs.");
106 }
107
108 private static void allocate() {
109 for (int i = 0; i < OBJECTS_TO_ALLOCATE; ++i) {
110 tmp = new byte[OBJECT_SIZE - BYTE_ARRAY_OVERHEAD];
111 }
112 }
113
114 private static void verifyRecording(Recording recording) throws Exception {
115 for (RecordedEvent event : Events.fromRecording(recording)) {
116 verify(event);
117 }
118 }
119
120 private static void verify(RecordedEvent event) {
121 if (Thread.currentThread().getId() != event.getThread().getJavaThreadId()) {
122 return;
123 }
124 long allocationSize = Events.assertField(event, "allocationSize").atLeast(1L).getValue();
125 long tlabSize = Events.assertField(event, "tlabSize").atLeast(allocationSize).getValue();
126 String className = Events.assertField(event, "objectClass.name").notEmpty().getValue();
127 if (className.equals(BYTE_ARRAY_CLASS_NAME) && (allocationSize == OBJECT_SIZE)) {
128 countAllTlabs++;
129 if (tlabSize == INITIAL_TLAB_SIZE + OBJECT_SIZE) {
130 countFullTlabs++;
131 }
132 }
133 }
134 }