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      1 /*
      2  * Copyright (C) 2014 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.util.concurrent;
     18 
     19 import static com.google.common.collect.Iterables.cycle;
     20 import static com.google.common.collect.Iterables.limit;
     21 
     22 import com.google.caliper.BeforeExperiment;
     23 import com.google.caliper.Benchmark;
     24 import com.google.caliper.Param;
     25 import com.google.caliper.api.Footprint;
     26 import com.google.caliper.api.VmOptions;
     27 import com.google.common.base.Supplier;
     28 import com.google.common.collect.ImmutableList;
     29 import com.google.common.primitives.Ints;
     30 
     31 import java.util.ArrayList;
     32 import java.util.Collections;
     33 import java.util.List;
     34 import java.util.Random;
     35 import java.util.concurrent.locks.Lock;
     36 import java.util.concurrent.locks.ReentrantLock;
     37 
     38 /**
     39  * A benchmark comparing the various striped implementations.
     40  */
     41 @VmOptions({"-Xms12g", "-Xmx12g", "-d64"})
     42 public class StripedBenchmark {
     43   private static final Supplier<Lock> LOCK_SUPPLIER = new Supplier<Lock>() {
     44     @Override public Lock get() {
     45       return new ReentrantLock();
     46     }
     47   };
     48 
     49   @Param({"2", "8", "64", "1024", "65536"}) int numStripes;
     50   @Param Impl impl;
     51 
     52   enum Impl {
     53     EAGER {
     54       @Override Striped<Lock> get(int stripes) {
     55         return Striped.lock(stripes);
     56       }
     57     },
     58     LAZY_SMALL {
     59       @Override Striped<Lock> get(int stripes) {
     60         return new Striped.SmallLazyStriped<Lock>(stripes, LOCK_SUPPLIER);
     61       }
     62     },
     63     LAZY_LARGE {
     64       @Override Striped<Lock> get(int stripes) {
     65         return new Striped.LargeLazyStriped<Lock>(stripes, LOCK_SUPPLIER);
     66       }
     67     };
     68 
     69     abstract Striped<Lock> get(int stripes);
     70   }
     71 
     72   private Striped<Lock> striped;
     73   private int[] stripes;
     74   private List<Integer> bulkGetSet;
     75 
     76   @BeforeExperiment void setUp() {
     77     this.striped = impl.get(numStripes);
     78     stripes = new int[numStripes];
     79     for (int i = 0; i < numStripes; i++) {
     80       stripes[i] = i;
     81     }
     82     List<Integer> asList = Ints.asList(stripes);
     83     Collections.shuffle(asList, new Random(0xdeadbeef));
     84 
     85     // do bulk gets with exactly 10 keys (possibly <10 stripes) (or less if numStripes is smaller)
     86     bulkGetSet = ImmutableList.copyOf(limit(cycle(asList), 10));
     87   }
     88 
     89   @Footprint Object sizeOfStriped() {
     90     return impl.get(numStripes);
     91   }
     92 
     93   // a place to put the locks in sizeOfPopulatedStriped so they don't get GC'd before we measure
     94   final List<Lock> locks = new ArrayList<Lock>(numStripes);
     95 
     96   @Footprint Object sizeOfPopulatedStriped() {
     97     locks.clear();
     98     Striped<Lock> striped = impl.get(numStripes);
     99     for (int i : stripes) {
    100       locks.add(striped.getAt(i));
    101     }
    102     return striped;
    103   }
    104 
    105   @Benchmark long timeConstruct(long reps) {
    106     long rvalue = 0;
    107     int numStripesLocal = numStripes;
    108     Impl implLocal = impl;
    109     for (long i = 0; i < reps; i++) {
    110       rvalue += implLocal.get(numStripesLocal).hashCode();
    111     }
    112     return rvalue;
    113   }
    114 
    115   @Benchmark long timeGetAt(long reps) {
    116     long rvalue = 0;
    117     int[] stripesLocal = stripes;
    118     int mask = numStripes - 1;
    119     Striped<Lock> stripedLocal = striped;
    120     for (long i = 0; i < reps; i++) {
    121       rvalue += stripedLocal.getAt(stripesLocal[(int) (i & mask)]).hashCode();
    122     }
    123     return rvalue;
    124   }
    125 
    126   @Benchmark long timeBulkGet(long reps) {
    127     long rvalue = 0;
    128     List<Integer> bulkGetSetLocal = bulkGetSet;
    129     Striped<Lock> stripedLocal = striped;
    130     for (long i = 0; i < reps; i++) {
    131       rvalue += stripedLocal.bulkGet(bulkGetSetLocal).hashCode();
    132     }
    133     return rvalue;
    134   }
    135 }
    136