1   /*
2    * Copyright (C) 2008 The Guava Authors
3    *
4    * Licensed under the Apache License, Version 2.0 (the "License");
5    * you may not use this file except in compliance with the License.
6    * You may obtain a copy of the License at
7    *
8    * http://www.apache.org/licenses/LICENSE-2.0
9    *
10   * Unless required by applicable law or agreed to in writing, software
11   * distributed under the License is distributed on an "AS IS" BASIS,
12   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13   * See the License for the specific language governing permissions and
14   * limitations under the License.
15   */
16  
17  package com.google.common.base;
18  
19  import com.google.caliper.Benchmark;
20  import com.google.common.base.Stopwatch;
21  
22  import java.util.concurrent.TimeUnit;
23  
24  /**
25   * Simple benchmark: create, start, read. This does not currently report the
26   * most useful result because it's ambiguous to what extent the stopwatch
27   * benchmark is being affected by GC.
28   *
29   * @author Kevin Bourrillion
30   */
31  public class StopwatchBenchmark {
32    @Benchmark long stopwatch(int reps) {
33      long total = 0;
34      for (int i = 0; i < reps; i++) {
35        Stopwatch s = Stopwatch.createStarted();
36        // here is where you would do something
37        total += s.elapsed(TimeUnit.NANOSECONDS);
38      }
39      return total;
40    }
41  
42    @Benchmark long manual(int reps) {
43      long total = 0;
44      for (int i = 0; i < reps; i++) {
45        long start = System.nanoTime();
46        // here is where you would do something
47        total += (System.nanoTime() - start);
48      }
49      return total;
50    }
51  }