1 /*
 2  * Copyright (c) 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 org.openjdk.bench.valhalla.array.walk;
24 
25 
26 import org.openjdk.jmh.annotations.BenchmarkMode;
27 import org.openjdk.jmh.annotations.Fork;
28 import org.openjdk.jmh.annotations.Measurement;
29 import org.openjdk.jmh.annotations.Mode;
30 import org.openjdk.jmh.annotations.OutputTimeUnit;
31 import org.openjdk.jmh.annotations.Param;
32 import org.openjdk.jmh.annotations.Scope;
33 import org.openjdk.jmh.annotations.State;
34 import org.openjdk.jmh.annotations.Warmup;
35 
36 import java.util.Random;
37 import java.util.concurrent.TimeUnit;
38 
39 @Fork(3)
40 @Warmup(iterations = 5, time = 1)
41 @Measurement(iterations = 5, time = 1)
42 @OutputTimeUnit(TimeUnit.NANOSECONDS)
43 @BenchmarkMode(Mode.AverageTime)
44 public class WalkBase {
45 
46     @State(Scope.Thread)
47     public static abstract class SizeState {
48 
49         @Param({
50                 "100",      // tiny size, to fit into all caches and check codegeneration quality
51                 "1000000"   // large size, to be out of all caches and memory effects
52         })
53         public int size;
54     }
55 
56     public static void shuffle(int[] a, Random rnd) {
57         for (int i = a.length; i > 1; i--) {
58             int idx = rnd.nextInt(i);
59             int tmp = a[i - 1];
60             a[i - 1] = a[idx];
61             a[idx] = tmp;
62         }
63 
64     }
65 
66     public static int[] makeRandomRing(int size) {
67         int[] A = new int[size - 1];
68         for (int i = 0; i < A.length; i++) {
69             A[i] = i + 1;
70         }
71         shuffle(A, new Random(42));
72         int[] a = new int[size];
73         int x = 0;
74         for (int i = 0; i < A.length; i++) {
75             x = a[x] = A[i];
76         }
77         a[x] = 0;
78         return a;
79     }
80 
81 }