jdk8-mips64-public/hotspot: test/gc/g1/TestStringDeduplicationTools.java@595c0f60d50d (annotated)

test/gc/g1/TestStringDeduplicationTools.java@595c0f60d50d (annotated)

test/gc/g1/TestStringDeduplicationTools.java

Tue, 18 Mar 2014 19:07:22 +0100

author: pliden
date: Tue, 18 Mar 2014 19:07:22 +0100
changeset 6413: 595c0f60d50d
child 6548: fd8ddf2d2f6b
permissions: -rw-r--r--

8029075: String deduplication in G1
Summary: Implementation of JEP 192, http://openjdk.java.net/jeps/192
Reviewed-by: brutisso, tschatzl, coleenp

 /*
  * Copyright (c) 2014, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License version 2 only, as
  * published by the Free Software Foundation.
  *
  * This code is distributed in the hope that it will be useful, but WITHOUT
  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  * version 2 for more details (a copy is included in the LICENSE file that
  * accompanied this code).
  *
  * You should have received a copy of the GNU General Public License version
  * 2 along with this work; if not, write to the Free Software Foundation,
  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  *
  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  * or visit www.oracle.com if you need additional information or have any
  * questions.
  */
 /*
  * Common code for string deduplication tests
  */
 import java.lang.management.*;
 import java.lang.reflect.*;
 import java.security.*;
 import java.util.*;
 import com.oracle.java.testlibrary.*;
 import sun.misc.*;
 class TestStringDeduplicationTools {
     private static final String YoungGC = "YoungGC";
     private static final String FullGC  = "FullGC";
     private static final int Xmn = 50;  // MB
     private static final int Xms = 100; // MB
     private static final int Xmx = 100; // MB
     private static final int MB = 1024 * 1024;
     private static final int StringLength = 50;
     private static Field valueField;
     private static Unsafe unsafe;
     private static byte[] dummy;
     static {
         try {
             Field field = Unsafe.class.getDeclaredField("theUnsafe");
             field.setAccessible(true);
             unsafe = (Unsafe)field.get(null);
             valueField = String.class.getDeclaredField("value");
             valueField.setAccessible(true);
         } catch (Exception e) {
             throw new RuntimeException(e);
         }
     }
     private static Object getValue(String string) {
         try {
             return valueField.get(string);
         } catch (Exception e) {
             throw new RuntimeException(e);
         }
     }
     private static void doFullGc(int numberOfTimes) {
         for (int i = 0; i < numberOfTimes; i++) {
             System.out.println("Begin: Full GC " + (i + 1) + "/" + numberOfTimes);
             System.gc();
             System.out.println("End: Full GC " + (i + 1) + "/" + numberOfTimes);
         }
     }
     private static void doYoungGc(int numberOfTimes) {
         // Provoke at least numberOfTimes young GCs
         final int objectSize = 128;
         final int maxObjectInYoung = (Xmn * MB) / objectSize;
         for (int i = 0; i < numberOfTimes; i++) {
             System.out.println("Begin: Young GC " + (i + 1) + "/" + numberOfTimes);
             for (int j = 0; j < maxObjectInYoung + 1; j++) {
                 dummy = new byte[objectSize];
             }
             System.out.println("End: Young GC " + (i + 1) + "/" + numberOfTimes);
         }
     }
     private static void forceDeduplication(int ageThreshold, String gcType) {
         // Force deduplication to happen by either causing a FullGC or a YoungGC.
         // We do several collections to also provoke a situation where the the
         // deduplication thread needs to yield while processing the queue. This
         // also tests that the references in the deduplication queue are adjusted
         // accordingly.
         if (gcType.equals(FullGC)) {
             doFullGc(3);
         } else {
             doYoungGc(ageThreshold + 3);
         }
     }
     private static String generateString(int id) {
         StringBuilder builder = new StringBuilder(StringLength);
         builder.append("DeduplicationTestString:" + id + ":");
         while (builder.length() < StringLength) {
             builder.append('X');
         }
         return builder.toString();
     }
     private static ArrayList<String> createStrings(int total, int unique) {
         System.out.println("Creating strings: total=" + total + ", unique=" + unique);
         if (total % unique != 0) {
             throw new RuntimeException("Total must be divisible by unique");
         }
         ArrayList<String> list = new ArrayList<String>(total);
         for (int j = 0; j < total / unique; j++) {
             for (int i = 0; i < unique; i++) {
                 list.add(generateString(i));
             }
         }
         return list;
     }
     private static void verifyStrings(ArrayList<String> list, int uniqueExpected) {
         for (;;) {
             // Check number of deduplicated strings
             ArrayList<Object> unique = new ArrayList<Object>(uniqueExpected);
             for (String string: list) {
                 Object value = getValue(string);
                 boolean uniqueValue = true;
                 for (Object obj: unique) {
                     if (obj == value) {
                         uniqueValue = false;
                         break;
                     }
                 }
                 if (uniqueValue) {
                     unique.add(value);
                 }
             }
             System.out.println("Verifying strings: total=" + list.size() +
                                ", uniqueFound=" + unique.size() +
                                ", uniqueExpected=" + uniqueExpected);
             if (unique.size() == uniqueExpected) {
                 System.out.println("Deduplication completed");
                 break;
             } else {
                 System.out.println("Deduplication not completed, waiting...");
                 // Give the deduplication thread time to complete
                 try {
                     Thread.sleep(1000);
                 } catch (Exception e) {
                     throw new RuntimeException(e);
                 }
             }
         }
     }
     private static OutputAnalyzer runTest(String... extraArgs) throws Exception {
         String[] defaultArgs = new String[] {
             "-Xmn" + Xmn + "m",
             "-Xms" + Xms + "m",
             "-Xmx" + Xmx + "m",
             "-XX:+UseG1GC",
             "-XX:+UnlockDiagnosticVMOptions",
             "-XX:+VerifyAfterGC" // Always verify after GC
         };
         ArrayList<String> args = new ArrayList<String>();
         args.addAll(Arrays.asList(defaultArgs));
         args.addAll(Arrays.asList(extraArgs));
         ProcessBuilder pb = ProcessTools.createJavaProcessBuilder(args.toArray(new String[args.size()]));
         OutputAnalyzer output = new OutputAnalyzer(pb.start());
         System.err.println(output.getStderr());
         System.out.println(output.getStdout());
         return output;
     }
     private static class DeduplicationTest {
         public static void main(String[] args) {
             System.out.println("Begin: DeduplicationTest");
             final int numberOfStrings = Integer.parseUnsignedInt(args[0]);
             final int numberOfUniqueStrings = Integer.parseUnsignedInt(args[1]);
             final int ageThreshold = Integer.parseUnsignedInt(args[2]);
             final String gcType = args[3];
             ArrayList<String> list = createStrings(numberOfStrings, numberOfUniqueStrings);
             forceDeduplication(ageThreshold, gcType);
             verifyStrings(list, numberOfUniqueStrings);
             System.out.println("End: DeduplicationTest");
         }
         public static OutputAnalyzer run(int numberOfStrings, int ageThreshold, String gcType, String... extraArgs) throws Exception {
             String[] defaultArgs = new String[] {
                 "-XX:+UseStringDeduplication",
                 "-XX:StringDeduplicationAgeThreshold=" + ageThreshold,
                 DeduplicationTest.class.getName(),
                 "" + numberOfStrings,
                 "" + numberOfStrings / 2,
                 "" + ageThreshold,
                 gcType
             };
             ArrayList<String> args = new ArrayList<String>();
             args.addAll(Arrays.asList(extraArgs));
             args.addAll(Arrays.asList(defaultArgs));
             return runTest(args.toArray(new String[args.size()]));
         }
     }
     private static class InternedTest {
         public static void main(String[] args) {
             // This test verifies that interned strings are always
             // deduplicated when being interned, and never after
             // being interned.
             System.out.println("Begin: InternedTest");
             final int ageThreshold = Integer.parseUnsignedInt(args[0]);
             final String baseString = "DeduplicationTestString:" + InternedTest.class.getName();
             // Create duplicate of baseString
             StringBuilder sb1 = new StringBuilder(baseString);
             String dupString1 = sb1.toString();
             if (getValue(dupString1) == getValue(baseString)) {
                 throw new RuntimeException("Values should not match");
             }
             // Force baseString to be inspected for deduplication
             // and be inserted into the deduplication hashtable.
             forceDeduplication(ageThreshold, FullGC);
             // Wait for deduplication to occur
             while (getValue(dupString1) != getValue(baseString)) {
                 System.out.println("Waiting...");
                 try {
                     Thread.sleep(100);
                 } catch (Exception e) {
                     throw new RuntimeException(e);
                 }
             }
             // Create a new duplicate of baseString
             StringBuilder sb2 = new StringBuilder(baseString);
             String dupString2 = sb2.toString();
             if (getValue(dupString2) == getValue(baseString)) {
                 throw new RuntimeException("Values should not match");
             }
             // Intern the new duplicate
             Object beforeInternedValue = getValue(dupString2);
             String internedString = dupString2.intern();
             if (internedString != dupString2) {
                 throw new RuntimeException("String should match");
             }
             if (getValue(internedString) != getValue(baseString)) {
                 throw new RuntimeException("Values should match");
             }
             // Check original value of interned string, to make sure
             // deduplication happened on the interned string and not
             // on the base string
             if (beforeInternedValue == getValue(baseString)) {
                 throw new RuntimeException("Values should not match");
             }
             System.out.println("End: InternedTest");
         }
         public static OutputAnalyzer run() throws Exception {
             return runTest("-XX:+PrintGC",
                            "-XX:+PrintGCDetails",
                            "-XX:+UseStringDeduplication",
                            "-XX:+PrintStringDeduplicationStatistics",
                            "-XX:StringDeduplicationAgeThreshold=" + DefaultAgeThreshold,
                            InternedTest.class.getName(),
                            "" + DefaultAgeThreshold);
         }
     }
     private static class MemoryUsageTest {
         public static void main(String[] args) {
             System.out.println("Begin: MemoryUsageTest");
             final boolean useStringDeduplication = Boolean.parseBoolean(args[0]);
             final int numberOfStrings = LargeNumberOfStrings;
             final int numberOfUniqueStrings = 1;
             ArrayList<String> list = createStrings(numberOfStrings, numberOfUniqueStrings);
             forceDeduplication(DefaultAgeThreshold, FullGC);
             if (useStringDeduplication) {
                 verifyStrings(list, numberOfUniqueStrings);
             }
             System.gc();
             System.out.println("Heap Memory Usage: " + ManagementFactory.getMemoryMXBean().getHeapMemoryUsage().getUsed());
             System.out.println("End: MemoryUsageTest");
         }
         public static OutputAnalyzer run(boolean useStringDeduplication) throws Exception {
             String[] extraArgs = new String[0];
             if (useStringDeduplication) {
                 extraArgs = new String[] {
                     "-XX:+UseStringDeduplication",
                     "-XX:+PrintStringDeduplicationStatistics",
                     "-XX:StringDeduplicationAgeThreshold=" + DefaultAgeThreshold
                 };
             }
             String[] defaultArgs = new String[] {
                 "-XX:+PrintGC",
                 "-XX:+PrintGCDetails",
                 MemoryUsageTest.class.getName(),
                 "" + useStringDeduplication
             };
             ArrayList<String> args = new ArrayList<String>();
             args.addAll(Arrays.asList(extraArgs));
             args.addAll(Arrays.asList(defaultArgs));
             return runTest(args.toArray(new String[args.size()]));
         }
     }
     /*
      * Tests
      */
     private static final int LargeNumberOfStrings = 10000;
     private static final int SmallNumberOfStrings = 10;
     private static final int MaxAgeThreshold      = 15;
     private static final int DefaultAgeThreshold  = 3;
     private static final int MinAgeThreshold      = 1;
     private static final int TooLowAgeThreshold   = MinAgeThreshold - 1;
     private static final int TooHighAgeThreshold  = MaxAgeThreshold + 1;
     public static void testYoungGC() throws Exception {
         // Do young GC to age strings to provoke deduplication
         OutputAnalyzer output = DeduplicationTest.run(LargeNumberOfStrings,
                                                       DefaultAgeThreshold,
                                                       YoungGC,
                                                       "-XX:+PrintGC",
                                                       "-XX:+PrintStringDeduplicationStatistics");
         output.shouldNotContain("Full GC");
         output.shouldContain("GC pause (G1 Evacuation Pause) (young)");
         output.shouldContain("GC concurrent-string-deduplication");
         output.shouldContain("Deduplicated:");
         output.shouldHaveExitValue(0);
     }
     public static void testFullGC() throws Exception {
         // Do full GC to age strings to provoke deduplication
         OutputAnalyzer output = DeduplicationTest.run(LargeNumberOfStrings,
                                                       DefaultAgeThreshold,
                                                       FullGC,
                                                       "-XX:+PrintGC",
                                                       "-XX:+PrintStringDeduplicationStatistics");
         output.shouldNotContain("GC pause (G1 Evacuation Pause) (young)");
         output.shouldContain("Full GC");
         output.shouldContain("GC concurrent-string-deduplication");
         output.shouldContain("Deduplicated:");
         output.shouldHaveExitValue(0);
     }
     public static void testTableResize() throws Exception {
         // Test with StringDeduplicationResizeALot
         OutputAnalyzer output = DeduplicationTest.run(LargeNumberOfStrings,
                                                       DefaultAgeThreshold,
                                                       YoungGC,
                                                       "-XX:+PrintGC",
                                                       "-XX:+PrintStringDeduplicationStatistics",
                                                       "-XX:+StringDeduplicationResizeALot");
         output.shouldContain("GC concurrent-string-deduplication");
         output.shouldContain("Deduplicated:");
         output.shouldNotContain("Resize Count: 0");
         output.shouldHaveExitValue(0);
     }
     public static void testTableRehash() throws Exception {
         // Test with StringDeduplicationRehashALot
         OutputAnalyzer output = DeduplicationTest.run(LargeNumberOfStrings,
                                                       DefaultAgeThreshold,
                                                       YoungGC,
                                                       "-XX:+PrintGC",
                                                       "-XX:+PrintStringDeduplicationStatistics",
                                                       "-XX:+StringDeduplicationRehashALot");
         output.shouldContain("GC concurrent-string-deduplication");
         output.shouldContain("Deduplicated:");
         output.shouldNotContain("Rehash Count: 0");
         output.shouldNotContain("Hash Seed: 0x0");
         output.shouldHaveExitValue(0);
     }
     public static void testAgeThreshold() throws Exception {
         OutputAnalyzer output;
         // Test with max age theshold
         output = DeduplicationTest.run(SmallNumberOfStrings,
                                        MaxAgeThreshold,
                                        YoungGC,
                                        "-XX:+PrintGC",
                                        "-XX:+PrintStringDeduplicationStatistics");
         output.shouldContain("GC concurrent-string-deduplication");
         output.shouldContain("Deduplicated:");
         output.shouldHaveExitValue(0);
         // Test with min age theshold
         output = DeduplicationTest.run(SmallNumberOfStrings,
                                        MinAgeThreshold,
                                        YoungGC,
                                        "-XX:+PrintGC",
                                        "-XX:+PrintStringDeduplicationStatistics");
         output.shouldContain("GC concurrent-string-deduplication");
         output.shouldContain("Deduplicated:");
         output.shouldHaveExitValue(0);
         // Test with too low age threshold
         output = DeduplicationTest.run(SmallNumberOfStrings,
                                        TooLowAgeThreshold,
                                        YoungGC);
         output.shouldContain("StringDeduplicationAgeThreshold of " + TooLowAgeThreshold +
                              " is invalid; must be between " + MinAgeThreshold + " and " + MaxAgeThreshold);
         output.shouldHaveExitValue(1);
         // Test with too high age threshold
         output = DeduplicationTest.run(SmallNumberOfStrings,
                                        TooHighAgeThreshold,
                                        YoungGC);
         output.shouldContain("StringDeduplicationAgeThreshold of " + TooHighAgeThreshold +
                              " is invalid; must be between " + MinAgeThreshold + " and " + MaxAgeThreshold);
         output.shouldHaveExitValue(1);
     }
     public static void testPrintOptions() throws Exception {
         OutputAnalyzer output;
         // Test without PrintGC and without PrintStringDeduplicationStatistics
         output = DeduplicationTest.run(SmallNumberOfStrings,
                                        DefaultAgeThreshold,
                                        YoungGC);
         output.shouldNotContain("GC concurrent-string-deduplication");
         output.shouldNotContain("Deduplicated:");
         output.shouldHaveExitValue(0);
         // Test with PrintGC but without PrintStringDeduplicationStatistics
         output = DeduplicationTest.run(SmallNumberOfStrings,
                                        DefaultAgeThreshold,
                                        YoungGC,
                                        "-XX:+PrintGC");
         output.shouldContain("GC concurrent-string-deduplication");
         output.shouldNotContain("Deduplicated:");
         output.shouldHaveExitValue(0);
     }
     public static void testInterned() throws Exception {
         // Test that interned strings are deduplicated before being interned
         OutputAnalyzer output = InternedTest.run();
         output.shouldHaveExitValue(0);
     }
     public static void testMemoryUsage() throws Exception {
         // Test that memory usage is reduced after deduplication
         OutputAnalyzer output;
         final String usagePattern = "Heap Memory Usage: (\\d+)";
         // Run without deduplication
         output = MemoryUsageTest.run(false);
         output.shouldHaveExitValue(0);
         final long memoryUsageWithoutDedup = Long.parseLong(output.firstMatch(usagePattern, 1));
         // Run with deduplication
         output = MemoryUsageTest.run(true);
         output.shouldHaveExitValue(0);
         final long memoryUsageWithDedup = Long.parseLong(output.firstMatch(usagePattern, 1));
         // Calculate expected memory usage with deduplication enabled. This calculation does
         // not take alignment and padding into account, so it's a conservative estimate.
         final long sizeOfChar = 2; // bytes
         final long bytesSaved = (LargeNumberOfStrings - 1) * (StringLength * sizeOfChar + unsafe.ARRAY_CHAR_BASE_OFFSET);
         final long memoryUsageWithDedupExpected = memoryUsageWithoutDedup - bytesSaved;
         System.out.println("Memory usage summary:");
         System.out.println("   memoryUsageWithoutDedup:      " + memoryUsageWithoutDedup);
         System.out.println("   memoryUsageWithDedup:         " + memoryUsageWithDedup);
         System.out.println("   memoryUsageWithDedupExpected: " + memoryUsageWithDedupExpected);
         if (memoryUsageWithDedup > memoryUsageWithDedupExpected) {
             throw new Exception("Unexpected memory usage, memoryUsageWithDedup should less or equal to memoryUsageWithDedupExpected");
         }
     }
 }

Mercurial > jdk8-mips64-public > hotspot / annotate

test/gc/g1/TestStringDeduplicationTools.java@595c0f60d50d (annotated)

test/gc/g1/TestStringDeduplicationTools.java