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  * @requires vm.gc.Shenandoah

    29  * @library /test/lib

    30  * @modules java.base/jdk.internal.misc:open

    31  * @modules java.base/java.lang:open

    32  *          java.management

    33  * @run main/othervm -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions -XX:+UseShenandoahGC -XX:ShenandoahGCHeuristics=passive      -XX:+ShenandoahDegeneratedGC -XX:+UseStringDeduplication -Xmx256M -Xlog:gc+stats TestStringDedup

    34  * @run main/othervm -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions -XX:+UseShenandoahGC -XX:ShenandoahGCHeuristics=passive      -XX:-ShenandoahDegeneratedGC -XX:+UseStringDeduplication -Xmx256M -Xlog:gc+stats TestStringDedup

    35  *

    36  * @run main/othervm -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions -XX:+UseShenandoahGC -XX:ShenandoahGCHeuristics=aggressive   -XX:+UseStringDeduplication -Xmx256M -Xlog:gc+stats TestStringDedup

    37  *

    38  * @run main/othervm -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions -XX:+UseShenandoahGC                                         -XX:+UseStringDeduplication -Xmx256M -Xlog:gc+stats TestStringDedup

    39  * @run main/othervm -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions -XX:+UseShenandoahGC -XX:ShenandoahGCHeuristics=traversal    -XX:+UseStringDeduplication -Xmx256M -Xlog:gc+stats TestStringDedup

    40  *

    41  * @run main/othervm -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions -XX:+UseShenandoahGC -XX:ShenandoahGCHeuristics=compact      -XX:+UseStringDeduplication -Xmx256M -Xlog:gc+stats TestStringDedup

    42  */

    43 

    44 import java.lang.reflect.*;

    45 import java.util.*;

    46 

    47 import sun.misc.*;

    48 

    49 public class TestStringDedup {

    50     private static Field valueField;

    51     private static Unsafe unsafe;

    52 

    53     private static final int UniqueStrings = 20;

    54 

    55     static {

    56         try {

    57             Field field = Unsafe.class.getDeclaredField("theUnsafe");

    58             field.setAccessible(true);

    59             unsafe = (Unsafe) field.get(null);

    60 

    61             valueField = String.class.getDeclaredField("value");

    62             valueField.setAccessible(true);

    63         } catch (Exception e) {

    64             throw new RuntimeException(e);

    65         }

    66     }

    67 

    68     private static Object getValue(String string) {

    69         try {

    70             return valueField.get(string);

    71         } catch (Exception e) {

    72             throw new RuntimeException(e);

    73         }

    74     }

    75 

    76     static class StringAndId {

    77         private String str;

    78         private int id;

    79 

    80         public StringAndId(String str, int id) {

    81             this.str = str;

    82             this.id = id;

    83         }

    84 

    85         public String str() {

    86             return str;

    87         }

    88 

    89         public int id() {

    90             return id;

    91         }

    92     }

    93 

    94     private static void generateStrings(ArrayList<StringAndId> strs, int unique_strs) {

    95         Random rn = new Random();

    96         for (int u = 0; u < unique_strs; u++) {

    97             int n = rn.nextInt() % 10;

    98             n = Math.max(n, 2);

    99             for (int index = 0; index < n; index++) {

   100                 strs.add(new StringAndId("Unique String " + u, u));

   101             }

   102         }

   103     }

   104 

   105     private static int verifyDedepString(ArrayList<StringAndId> strs) {

   106         HashMap<Object, StringAndId> seen = new HashMap<>();

   107         int total = 0;

   108         int dedup = 0;

   109 

   110         for (StringAndId item : strs) {

   111             total++;

   112             StringAndId existing_item = seen.get(getValue(item.str()));

   113             if (existing_item == null) {

   114                 seen.put(getValue(item.str()), item);

   115             } else {

   116                 if (item.id() != existing_item.id() ||

   117                         !item.str().equals(existing_item.str())) {

   118                     System.out.println("StringDedup error:");

   119                     System.out.println("String: " + item.str() + " != " + existing_item.str());

   120                     throw new RuntimeException("StringDedup Test failed");

   121                 } else {

   122                     dedup++;

   123                 }

   124             }

   125         }

   126         System.out.println("Dedup: " + dedup + "/" + total + " unique: " + (total - dedup));

   127         return (total - dedup);

   128     }

   129 

   130     public static void main(String[] args) {

   131         ArrayList<StringAndId> astrs = new ArrayList<>();

   132         generateStrings(astrs, UniqueStrings);

   133         System.gc();

   134         System.gc();

   135         System.gc();

   136         System.gc();

   137         System.gc();

   138 

   139         if (verifyDedepString(astrs) != UniqueStrings) {

   140             // Can not guarantee all strings are deduplicated, there can

   141             // still have pending items in queues.

   142             System.out.println("Not all strings are deduplicated");

   143         }

   144     }

   145 }