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.vm.compiler;
  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.Param;
  30 import org.openjdk.jmh.annotations.Scope;
  31 import org.openjdk.jmh.annotations.Setup;
  32 import org.openjdk.jmh.annotations.State;
  33 
  34 import java.util.concurrent.TimeUnit;
  35 
  36 /**
  37  * Tests speed of multiplication calculations with constants.
  38  */
  39 @BenchmarkMode(Mode.AverageTime)
  40 @OutputTimeUnit(TimeUnit.NANOSECONDS)
  41 @State(Scope.Thread)
  42 public class Multiplication {
  43 
  44     @Param("500")
  45     private int arraySize;
  46 
  47     private long[] longArraySmall, longArrayBig;
  48 
  49     @Setup
  50     public void setupSubclass() {
  51         longArraySmall = new long[arraySize];
  52         longArrayBig = new long[arraySize];
  53 
  54         /*
  55          * small values always have higher 32 bits cleared. big values always
  56          * have higher 32 bits set.
  57          */
  58         for (int i = 0; i < arraySize; i++) {
  59             longArraySmall[i] = 100L * i + i;
  60             longArrayBig[i] = ((100L * i + i) << 32) + 4543 + i * 4;
  61         }
  62     }
  63 
  64     /* helper for small constant benchmarks. */
  65     private static long smallConstantHelper(long[] values) {
  66         long sum = 0;
  67         for (long value : values) {
  68             sum += value * 453543L;
  69         }
  70         return sum;
  71     }
  72 
  73     /* helper for big constant benchmarks. */
  74     private static long bigConstantHelper(long[] values) {
  75         long sum = 0;
  76         for (long value : values) {
  77             sum += value * 4554345533543L;
  78         }
  79         return sum;
  80     }
  81 
  82     /**
  83      * Test multiplications of longs. One of the operands is a small constant and the other is a variable that always is
  84      * small.
  85      */
  86     @Benchmark
  87     public long testLongSmallVariableSmallConstantMul() {
  88         return smallConstantHelper(longArraySmall);
  89     }
  90 
  91     /**
  92      * Test multiplications of longs. One of the operands is a big constant and the other is a variable that always is
  93      * small.
  94      */
  95     @Benchmark
  96     public long testLongSmallVariableBigConstantMul() {
  97         return bigConstantHelper(longArraySmall);
  98     }
  99 
 100     /**
 101      * Test multiplications of longs. One of the operands is a small constant and the other is a variable that always is
 102      * big.
 103      */
 104     @Benchmark
 105     public long testLongBigVariableSmallConstantMul() {
 106         return smallConstantHelper(longArrayBig);
 107     }
 108 
 109     /**
 110      * Test multiplications of longs. One of the operands is a big constant and the other is a variable that always is
 111      * big.
 112      */
 113     @Benchmark
 114     public long testLongBigVariableBigConstantMul() {
 115         return bigConstantHelper(longArrayBig);
 116     }
 117 
 118 }