1 /*
   2  * Copyright (c) 2017, 2018, Red Hat, Inc. All rights reserved.
   3  *
   4  * This code is free software; you can redistribute it and/or modify it
   5  * under the terms of the GNU General Public License version 2 only, as
   6  * published by the Free Software Foundation.
   7  *
   8  * This code is distributed in the hope that it will be useful, but WITHOUT
   9  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  10  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  11  * version 2 for more details (a copy is included in the LICENSE file that
  12  * accompanied this code).
  13  *
  14  * You should have received a copy of the GNU General Public License version
  15  * 2 along with this work; if not, write to the Free Software Foundation,
  16  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  17  *
  18  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  19  * or visit www.oracle.com if you need additional information or have any
  20  * questions.
  21  *
  22  */
  23 
  24  /*
  25  * @test TestStringDedup
  26  * @summary Test Shenandoah string deduplication implementation
  27  * @key gc
  28  *
  29  * @run main/othervm -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions -XX:+UseShenandoahGC -XX:ShenandoahGCHeuristics=passive      -XX:+ShenandoahDegeneratedGC -XX:+UseStringDeduplication -Xmx256M TestStringDedup
  30  * @run main/othervm -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions -XX:+UseShenandoahGC -XX:ShenandoahGCHeuristics=passive      -XX:-ShenandoahDegeneratedGC -XX:+UseStringDeduplication -Xmx256M TestStringDedup
  31  *
  32  * @run main/othervm -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions -XX:+UseShenandoahGC                                         -XX:+UseStringDeduplication -Xmx256M TestStringDedup
  33  * @run main/othervm -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions -XX:+UseShenandoahGC -XX:ShenandoahGCHeuristics=aggressive   -XX:+UseStringDeduplication -Xmx256M TestStringDedup
  34  * @run main/othervm -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions -XX:+UseShenandoahGC -XX:ShenandoahGCHeuristics=compact      -XX:+UseStringDeduplication -Xmx256M TestStringDedup
  35  */
  36 
  37 import java.lang.reflect.*;
  38 import java.util.*;
  39 
  40 import sun.misc.*;
  41 
  42 public class TestStringDedup {
  43     private static Field valueField;
  44     private static Unsafe unsafe;
  45 
  46     private static final int UniqueStrings = 20;
  47 
  48     static {
  49         try {
  50             Field field = Unsafe.class.getDeclaredField("theUnsafe");
  51             field.setAccessible(true);
  52             unsafe = (Unsafe) field.get(null);
  53 
  54             valueField = String.class.getDeclaredField("value");
  55             valueField.setAccessible(true);
  56         } catch (Exception e) {
  57             throw new RuntimeException(e);
  58         }
  59     }
  60 
  61     private static Object getValue(String string) {
  62         try {
  63             return valueField.get(string);
  64         } catch (Exception e) {
  65             throw new RuntimeException(e);
  66         }
  67     }
  68 
  69     static class StringAndId {
  70         private String str;
  71         private int id;
  72 
  73         public StringAndId(String str, int id) {
  74             this.str = str;
  75             this.id = id;
  76         }
  77 
  78         public String str() {
  79             return str;
  80         }
  81 
  82         public int id() {
  83             return id;
  84         }
  85     }
  86 
  87     private static void generateStrings(ArrayList<StringAndId> strs, int unique_strs) {
  88         Random rn = new Random();
  89         for (int u = 0; u < unique_strs; u++) {
  90             int n = rn.nextInt() % 10;
  91             n = Math.max(n, 2);
  92             for (int index = 0; index < n; index++) {
  93                 strs.add(new StringAndId("Unique String " + u, u));
  94             }
  95         }
  96     }
  97 
  98     private static int verifyDedepString(ArrayList<StringAndId> strs) {
  99         HashMap<Object, StringAndId> seen = new HashMap<>();
 100         int total = 0;
 101         int dedup = 0;
 102 
 103         for (StringAndId item : strs) {
 104             total++;
 105             StringAndId existing_item = seen.get(getValue(item.str()));
 106             if (existing_item == null) {
 107                 seen.put(getValue(item.str()), item);
 108             } else {
 109                 if (item.id() != existing_item.id() ||
 110                         !item.str().equals(existing_item.str())) {
 111                     System.out.println("StringDedup error:");
 112                     System.out.println("String: " + item.str() + " != " + existing_item.str());
 113                     throw new RuntimeException("StringDedup Test failed");
 114                 } else {
 115                     dedup++;
 116                 }
 117             }
 118         }
 119         System.out.println("Dedup: " + dedup + "/" + total + " unique: " + (total - dedup));
 120         return (total - dedup);
 121     }
 122 
 123     public static void main(String[] args) {
 124         ArrayList<StringAndId> astrs = new ArrayList<>();
 125         generateStrings(astrs, UniqueStrings);
 126         System.gc();
 127         System.gc();
 128         System.gc();
 129         System.gc();
 130         System.gc();
 131 
 132         if (verifyDedepString(astrs) != UniqueStrings) {
 133             // Can not guarantee all strings are deduplicated, there can
 134             // still have pending items in queues.
 135             System.out.println("Not all strings are deduplicated");
 136         }
 137     }
 138 }