1 /*
2  * Copyright (c) 2014, 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
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17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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22  */
23 package org.openjdk.bench.java.lang.invoke;
24 
25 import org.openjdk.jmh.annotations.Benchmark;
26 import org.openjdk.jmh.annotations.BenchmarkMode;
27 import org.openjdk.jmh.annotations.Mode;
28 import org.openjdk.jmh.annotations.OutputTimeUnit;
29 import org.openjdk.jmh.annotations.Scope;
30 import org.openjdk.jmh.annotations.Setup;
31 import org.openjdk.jmh.annotations.State;
32 
33 import java.lang.invoke.MethodHandle;
34 import java.lang.invoke.MethodHandles;
35 import java.util.concurrent.TimeUnit;
36 
37 /**
38  * Benchmark assesses the performance of MethodHandles.arrayElementSetter
39  *
40  * @author Aleksey Shipilev (aleksey.shipilev@oracle.com)
41  */
42 @BenchmarkMode(Mode.AverageTime)
43 @OutputTimeUnit(TimeUnit.NANOSECONDS)
44 @State(Scope.Thread)
45 public class MethodHandlesArrayElementSetter {
46 
47     /**
48      * Implementation notes:
49      *   - creating simple array, and accessing the middle element
50      *   - might have done iteration over array, but that will measure pipelining effects instead
51      *   - volatile modifier on array breaks the DCE, which would otherwise eliminate the array store
52      *   - the array is not shared to prevent true sharing
53      *   - the array is large enough to prevent false sharing
54      */
55 
56     private static final int SIZE = 1024;
57     private static final int POS = SIZE/2;
58 
59     private static MethodHandle mh;
60     private volatile int[] array;
61 
62     @Setup
setup()63     public void setup() throws Throwable {
64         array = new int[SIZE];
65         for (int i = 0; i < SIZE; i++) {
66             array[i] = i;
67         }
68         mh = MethodHandles.arrayElementSetter(int[].class);
69     }
70 
71     @Benchmark
testCreate()72     public MethodHandle testCreate() {
73         return MethodHandles.arrayElementSetter(int[].class);
74     }
75 
76     @Benchmark
baselineRaw()77     public void baselineRaw() {
78         access(array, POS, 1);
79     }
80 
81     @Benchmark
testSetter()82     public void testSetter() throws Throwable {
83         mh.invoke(array, POS, 1);
84     }
85 
access(int[] array, int pos, int v)86     public void access(int[] array, int pos, int v) {
87         array[pos] = v;
88     }
89 
90 }
91