1/*
2 * Copyright (C) 2011 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
17package com.google.common.cache;
18
19import com.google.caliper.BeforeExperiment;
20import com.google.caliper.Benchmark;
21import com.google.caliper.Param;
22import com.google.common.cache.LocalCache.ReferenceEntry;
23import com.google.common.cache.LocalCache.Segment;
24
25/**
26 * Benchmark for {@code LocalCache.Segment.removeEntryFromChain}.
27 *
28 * @author Charles Fry
29 */
30public class ChainBenchmark {
31
32  @Param({"1", "2", "3", "4", "5", "6"}) int length;
33
34  private Segment<Object, Object> segment;
35  private ReferenceEntry<Object, Object> head;
36  private ReferenceEntry<Object, Object> chain;
37
38  @BeforeExperiment
39  void setUp() {
40    LocalCache<Object, Object> cache = new LocalCache<Object, Object>(
41        CacheBuilder.newBuilder()
42            .concurrencyLevel(1), null);
43    segment = cache.segments[0];
44    chain = null;
45    for (int i = 0; i < length; i++) {
46      Object key = new Object();
47      chain = segment.newEntry(key, cache.hash(key), chain);
48      if (i == 0) {
49        head = chain;
50      }
51    }
52  }
53
54  @Benchmark int time(int reps) {
55    int dummy = 0;
56    for (int i = 0; i < reps; i++) {
57      segment.removeEntryFromChain(chain, head);
58      dummy += segment.count;
59    }
60    return dummy;
61  }
62}
63