1 /*
   2  * Copyright (c) 2018, 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 
  24 
  25 package micro.benchmarks;
  26 
  27 import java.math.BigInteger;
  28 import java.util.Random;
  29 
  30 import org.openjdk.jmh.annotations.Benchmark;
  31 import org.openjdk.jmh.annotations.Scope;
  32 import org.openjdk.jmh.annotations.State;
  33 import org.openjdk.jmh.annotations.Warmup;
  34 
  35 /*
  36  * Benchmarks cost of BigInteger intrinsics:
  37  *
  38  *      montgomeryMultiply, montgomerySquare, mulAdd, multiplyToLen, squareToLen
  39  */
  40 public class BigIntegerBenchmark extends BenchmarkBase {
  41 
  42     @State(Scope.Benchmark)
  43     public static class ThreadState {
  44         BigInteger[] data = randomBigInteger(100);
  45         BigInteger[] result = new BigInteger[100];
  46 
  47         static BigInteger[] randomBigInteger(int len) {
  48             BigInteger[] data = new BigInteger[len];
  49             Random r = new Random(17);
  50             for (int i = 0; i < data.length; i++) {
  51                 data[i] = new BigInteger(r.nextInt(16384) + 512, r);
  52             }
  53             return data;
  54         }
  55     }
  56 
  57     @Benchmark
  58     @Warmup(iterations = 5)
  59     public void bigIntMul(ThreadState state) {
  60         BigInteger[] data = state.data;
  61         for (int i = 1; i < data.length; i++) {
  62             BigInteger[] result = state.result;
  63             result[i] = data[i - 1].multiply(data[i]);
  64         }
  65     }
  66 
  67     @Benchmark
  68     @Warmup(iterations = 5)
  69     public void bigIntMulAdd(ThreadState state) {
  70         BigInteger[] data = state.data;
  71         for (int i = 0; i < data.length; i++) {
  72             BigInteger[] result = state.result;
  73             // Using BigInteger.square() when length is suitable.
  74             // Using BigInteger.mulAdd() when length is suitable.
  75             result[i] = data[i].multiply(data[i]);
  76         }
  77     }
  78 
  79     @Benchmark
  80     @Warmup(iterations = 5)
  81     public void bigIntMontgomeryMul(ThreadState state) {
  82         BigInteger[] data = state.data;
  83         BigInteger exp = BigInteger.valueOf(2);
  84 
  85         for (int i = 0; i < data.length; i++) {
  86             BigInteger[] result = state.result;
  87             int rsh = data[i].bitLength() / 2 + 3;
  88             // The "odd" path.
  89             // Using BigInteger.montgomeryMultiply().
  90             // Using BigInteger.montgomerySquare().
  91             // Using BigInteger.mulAdd() when length is suitable.
  92             result[i] = data[i].modPow(exp, data[i].shiftRight(rsh).setBit(0));
  93         }
  94     }
  95 
  96     @Benchmark
  97     @Warmup(iterations = 5)
  98     public void bigIntMontgomerySqr(ThreadState state) {
  99         BigInteger[] data = state.data;
 100         BigInteger exp = BigInteger.valueOf(2);
 101 
 102         for (int i = 0; i < data.length; i++) {
 103             BigInteger[] result = state.result;
 104             int rsh = data[i].bitLength() / 2 + 3;
 105             // The "even" path.
 106             // Using BigInteger.montgomeryMultiply().
 107             // Using BigInteger.montgomerySquare().
 108             // Using BigInteger.mulAdd() when length is suitable.
 109             result[i] = data[i].modPow(exp, data[i].shiftRight(rsh).clearBit(0));
 110         }
 111     }
 112 }