1 /*
 2  * Copyright Amazon.com Inc. 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 
25 package org.openjdk.bench.vm.gc.barriers.reads;
26 
27 import org.openjdk.jmh.annotations.*;
28 import org.openjdk.jmh.infra.Blackhole;
29 
30 import java.util.concurrent.TimeUnit;
31 
32 @Warmup(iterations = 3, time = 1, timeUnit = TimeUnit.SECONDS)
33 @Measurement(iterations = 3, time = 1, timeUnit = TimeUnit.SECONDS)
34 @Fork(value = 3, jvmArgs = {"-Xmx1g", "-Xms1g"})
35 @BenchmarkMode(Mode.AverageTime)
36 @OutputTimeUnit(TimeUnit.NANOSECONDS)
37 @State(Scope.Thread)
38 public class List {
39 
40     @Param({"1", "16", "256", "4096", "65536"})
41     public int depth;
42 
43     private Node root;
44 
45     @Setup(Level.Trial)
46     public void setup() {
47         for (int d = 0; d < depth; d++) {
48             root = new Node(root, d);
49         }
50         System.gc();
51     }
52 
53     @Benchmark
54     public int walk() {
55         Node n = root;
56         while (n.next != null) {
57             n = n.next;
58         }
59         return n.payload;
60     }
61 
62     public static class Node {
63         Node next;
64         int payload;
65 
66         Node(Node next, int payload) {
67             this.next = next;
68             this.payload = payload;
69         }
70     }
71 }