/*
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* Copyright (C) 2010 Google Inc.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package benchmarks.regression;
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import com.google.caliper.BeforeExperiment;
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import com.google.caliper.Param;
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import java.util.ArrayList;
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import java.util.Collections;
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import java.util.List;
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import java.util.PriorityQueue;
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import java.util.Random;
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public class PriorityQueueBenchmark {
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@Param({"100", "1000", "10000"}) private int queueSize;
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@Param({"0", "25", "50", "75", "100"}) private int hitRate;
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private PriorityQueue<Integer> pq;
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private PriorityQueue<Integer> usepq;
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private List<Integer> seekElements;
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private Random random = new Random(189279387L);
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@BeforeExperiment
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protected void setUp() throws Exception {
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pq = new PriorityQueue<Integer>();
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usepq = new PriorityQueue<Integer>();
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seekElements = new ArrayList<Integer>();
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List<Integer> allElements = new ArrayList<Integer>();
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int numShared = (int)(queueSize * ((double)hitRate / 100));
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// the total number of elements we require to engineer a hit rate of hitRate%
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int totalElements = 2 * queueSize - numShared;
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for (int i = 0; i < totalElements; i++) {
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allElements.add(i);
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}
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// shuffle these elements so that we get a reasonable distribution of missed elements
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Collections.shuffle(allElements, random);
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// add shared elements
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for (int i = 0; i < numShared; i++) {
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pq.add(allElements.get(i));
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seekElements.add(allElements.get(i));
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}
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// add priority queue only elements (these won't be touched)
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for (int i = numShared; i < queueSize; i++) {
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pq.add(allElements.get(i));
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}
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// add non-priority queue elements (these will be misses)
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for (int i = queueSize; i < totalElements; i++) {
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seekElements.add(allElements.get(i));
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}
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usepq = new PriorityQueue<Integer>(pq);
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// shuffle again so that elements are accessed in a different pattern than they were
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// inserted
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Collections.shuffle(seekElements, random);
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}
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public boolean timeRemove(int reps) {
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boolean dummy = false;
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int elementsSize = seekElements.size();
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// At most allow the queue to empty 10%.
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int resizingThreshold = queueSize / 10;
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for (int i = 0; i < reps; i++) {
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// Reset queue every so often. This will be called more often for smaller
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// queueSizes, but since a copy is linear, it will also cost proportionally
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// less, and hopefully it will approximately balance out.
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if (i % resizingThreshold == 0) {
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usepq = new PriorityQueue<Integer>(pq);
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}
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dummy = usepq.remove(seekElements.get(i % elementsSize));
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}
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return dummy;
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}
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}
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