1 /*
2  * Copyright (C) 2010 Google Inc.
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 benchmarks.regression;
18 
19 import com.google.caliper.BeforeExperiment;
20 import com.google.caliper.Param;
21 import java.util.ArrayList;
22 import java.util.Collections;
23 import java.util.List;
24 import java.util.PriorityQueue;
25 import java.util.Random;
26 
27 public class PriorityQueueBenchmark {
28     @Param({"100", "1000", "10000"}) private int queueSize;
29     @Param({"0", "25", "50", "75", "100"}) private int hitRate;
30 
31     private PriorityQueue<Integer> pq;
32     private PriorityQueue<Integer> usepq;
33     private List<Integer> seekElements;
34     private Random random = new Random(189279387L);
35 
36     @BeforeExperiment
setUp()37     protected void setUp() throws Exception {
38         pq = new PriorityQueue<Integer>();
39         usepq = new PriorityQueue<Integer>();
40         seekElements = new ArrayList<Integer>();
41         List<Integer> allElements = new ArrayList<Integer>();
42         int numShared = (int)(queueSize * ((double)hitRate / 100));
43         // the total number of elements we require to engineer a hit rate of hitRate%
44         int totalElements = 2 * queueSize - numShared;
45         for (int i = 0; i < totalElements; i++) {
46             allElements.add(i);
47         }
48         // shuffle these elements so that we get a reasonable distribution of missed elements
49         Collections.shuffle(allElements, random);
50         // add shared elements
51         for (int i = 0; i < numShared; i++) {
52             pq.add(allElements.get(i));
53             seekElements.add(allElements.get(i));
54         }
55         // add priority queue only elements (these won't be touched)
56         for (int i = numShared; i < queueSize; i++) {
57             pq.add(allElements.get(i));
58         }
59         // add non-priority queue elements (these will be misses)
60         for (int i = queueSize; i < totalElements; i++) {
61             seekElements.add(allElements.get(i));
62         }
63         usepq = new PriorityQueue<Integer>(pq);
64         // shuffle again so that elements are accessed in a different pattern than they were
65         // inserted
66         Collections.shuffle(seekElements, random);
67     }
68 
timeRemove(int reps)69     public boolean timeRemove(int reps) {
70         boolean fake = false;
71         int elementsSize = seekElements.size();
72         // At most allow the queue to empty 10%.
73         int resizingThreshold = queueSize / 10;
74         for (int i = 0; i < reps; i++) {
75             // Reset queue every so often. This will be called more often for smaller
76             // queueSizes, but since a copy is linear, it will also cost proportionally
77             // less, and hopefully it will approximately balance out.
78             if (i % resizingThreshold == 0) {
79                 usepq = new PriorityQueue<Integer>(pq);
80             }
81             fake = usepq.remove(seekElements.get(i % elementsSize));
82         }
83         return fake;
84     }
85 }
86