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
  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.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
  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
  72     public MethodHandle testCreate() {
  73         return MethodHandles.arrayElementSetter(int[].class);
  74     }
  75 
  76     @Benchmark
  77     public void baselineRaw() {
  78         access(array, POS, 1);
  79     }
  80 
  81     @Benchmark
  82     public void testSetter() throws Throwable {
  83         mh.invoke(array, POS, 1);
  84     }
  85 
  86     public void access(int[] array, int pos, int v) {
  87         array[pos] = v;
  88     }
  89 
  90 }