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.ops.ref;
  24 
  25 import org.openjdk.bench.java.util.stream.ops.LongAccumulator;
  26 import org.openjdk.jmh.annotations.Benchmark;
  27 import org.openjdk.jmh.annotations.BenchmarkMode;
  28 import org.openjdk.jmh.annotations.Mode;
  29 import org.openjdk.jmh.annotations.OutputTimeUnit;
  30 import org.openjdk.jmh.annotations.Param;
  31 import org.openjdk.jmh.annotations.Scope;
  32 import org.openjdk.jmh.annotations.State;
  33 
  34 import java.util.concurrent.TimeUnit;
  35 import java.util.stream.LongStream;
  36 
  37 /**
  38  * Benchmark for uniqueElements() operation.
  39  */
  40 @BenchmarkMode(Mode.Throughput)
  41 @OutputTimeUnit(TimeUnit.SECONDS)
  42 @State(Scope.Thread)
  43 public class UniqueElements {
  44 
  45     /**
  46      * Implementation notes:
  47      *   - parallel version requires thread-safe sink, we use the same for sequential version for better comparison
  48      *   - operations are explicit inner classes to untangle unwanted lambda effects
  49      *   - the result of applying consecutive operations is the same, in order to have the same number of elements in sink
  50      */
  51 
  52     @Param("100000")
  53     private int size;
  54 
  55     @Benchmark
  56     public long seq_invoke() {
  57         return LongStream.range(0, size)
  58                 .boxed()
  59                 .distinct()
  60                 .collect(LongAccumulator::new, LongAccumulator::add, LongAccumulator::merge).get();
  61     }
  62 
  63     @Benchmark
  64     public long par_invoke() {
  65         return LongStream.range(0, size).parallel()
  66                 .boxed()
  67                 .distinct()
  68                 .collect(LongAccumulator::new, LongAccumulator::add, LongAccumulator::merge).get();
  69     }
  70 
  71     @Benchmark
  72     public long seq_chain() {
  73         return LongStream.range(0, size)
  74                 .boxed()
  75                 .distinct()
  76                 .distinct()
  77                 .distinct()
  78                 .collect(LongAccumulator::new, LongAccumulator::add, LongAccumulator::merge).get();
  79     }
  80 
  81     @Benchmark
  82     public long par_chain() {
  83         return LongStream.range(0, size).parallel()
  84                 .boxed()
  85                 .distinct()
  86                 .distinct()
  87                 .distinct()
  88                 .collect(LongAccumulator::new, LongAccumulator::add, LongAccumulator::merge).get();
  89     }
  90 
  91 }