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.util.stream;
  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 import java.util.function.LongBinaryOperator;
  36 import java.util.stream.LongStream;
  37 
  38 /**
  39  * Benchmark for checking different reduce schemes.
  40  */
  41 @BenchmarkMode(Mode.Throughput)
  42 @OutputTimeUnit(TimeUnit.SECONDS)
  43 @State(Scope.Thread)
  44 public class Reducers {
  45 
  46     /**
  47      * Implementation notes:
  48      *   - parallel version requires thread-safe sink, we use the same for sequential version for better comparison
  49      *   - operations are explicit inner classes to untangle unwanted lambda effects
  50      *   - the result of applying consecutive operations is the same, in order to have the same number of elements in sink
  51      */
  52 
  53     @Param("100000")
  54     private int size;
  55 
  56     private LongBinaryOperator op;
  57 
  58     @Setup
  59     public void setup() {
  60         op = new LongBinaryOperator() {
  61             @Override
  62             public long applyAsLong(long l, long r) {
  63                 return (l > r) ? l : r;
  64             }
  65         };
  66     }
  67 
  68     @Benchmark
  69     public long seq_reduce() {
  70         return LongStream.range(0, size).reduce(op).getAsLong();
  71     }
  72 
  73     @Benchmark
  74     public long par_reduce() {
  75         return LongStream.range(0, size).parallel().reduce(op).getAsLong();
  76     }
  77 
  78     @Benchmark
  79     public long seq_reduce_base() {
  80         return LongStream.range(0, size).reduce(0L, op);
  81     }
  82 
  83     @Benchmark
  84     public long par_reduce_base() {
  85         return LongStream.range(0, size).parallel().reduce(0L, op);
  86     }
  87 
  88 
  89 }