1 /*
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  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
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  23 
  24 /*
  25  * @test TestOldGenCollectionUsage.java
  26  * @bug 8195115
  27  * @summary G1 Old Gen's CollectionUsage.used is zero after mixed GC which is incorrect
  28  * @key gc
  29  * @requires vm.gc.G1
  30  * @requires vm.opt.MaxGCPauseMillis == "null"
  31  * @library /test/lib
  32  * @modules java.base/jdk.internal.misc
  33  * @modules java.management
  34  * @build sun.hotspot.WhiteBox
  35  * @run driver ClassFileInstaller sun.hotspot.WhiteBox
  36  * @run main/othervm -Xbootclasspath/a:. -XX:+UseG1GC -XX:+UnlockExperimentalVMOptions -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI -verbose:gc -XX:SurvivorRatio=1 -Xmx12m -Xms12m -XX:MaxTenuringThreshold=1 -XX:InitiatingHeapOccupancyPercent=100 -XX:-G1UseAdaptiveIHOP -XX:G1MixedGCCountTarget=4 -XX:MaxGCPauseMillis=30000 -XX:G1HeapRegionSize=1m -XX:G1HeapWastePercent=0 -XX:G1MixedGCLiveThresholdPercent=100 TestOldGenCollectionUsage
  37  */
  38 
  39 import jdk.test.lib.Asserts;
  40 import sun.hotspot.WhiteBox;
  41 
  42 import java.util.ArrayList;
  43 import java.util.List;
  44 import java.util.Collections;
  45 
  46 import java.lang.management.*;
  47 
  48 // 8195115 says that for the "G1 Old Gen" MemoryPool, CollectionUsage.used
  49 // is zero for G1 after a mixed collection, which is incorrect.
  50 
  51 public class TestOldGenCollectionUsage {
  52 
  53     private String poolName = "G1 Old Gen";
  54     private String collectorName = "G1 Young Generation";
  55 
  56     public static void main(String [] args) throws Exception {
  57         TestOldGenCollectionUsage t = new TestOldGenCollectionUsage();
  58         t.run();
  59     }
  60 
  61     public TestOldGenCollectionUsage() {
  62         System.out.println("Monitor G1 Old Gen pool with G1 Young Generation collector.");
  63     }
  64 
  65     public void run() {
  66         // Find memory pool and collector
  67         List<MemoryPoolMXBean> pools = ManagementFactory.getMemoryPoolMXBeans();
  68         MemoryPoolMXBean pool = null;
  69         boolean foundPool = false;
  70         for (int i = 0; i < pools.size(); i++) {
  71             pool = pools.get(i);
  72             String name = pool.getName();
  73             if (name.contains(poolName)) {
  74                 System.out.println("Found pool: " + name);
  75                 foundPool = true;
  76                 break;
  77             }
  78         }
  79         if (!foundPool) {
  80             throw new RuntimeException(poolName + " not found, test with -XX:+UseG1GC");
  81         }
  82 
  83         List<GarbageCollectorMXBean> collectors = ManagementFactory.getGarbageCollectorMXBeans();
  84         GarbageCollectorMXBean collector = null;
  85         boolean foundCollector = false;
  86         for (int i = 0; i < collectors.size(); i++) {
  87             collector = collectors.get(i);
  88             String name = collector.getName();
  89             if (name.contains(collectorName)) {
  90                 System.out.println("Found collector: " + name);
  91                 foundCollector = true;
  92                 break;
  93             }
  94         }
  95         if (!foundCollector) {
  96             throw new RuntimeException(collectorName + " not found, test with -XX:+UseG1GC");
  97         }
  98 
  99         MixedGCProvoker gcProvoker = new MixedGCProvoker();
 100         gcProvoker.allocateOldObjects();
 101 
 102         // Verify no non-zero result was stored
 103         long usage = pool.getCollectionUsage().getUsed();
 104         System.out.println(poolName + ": usage after GC = " + usage);
 105         if (usage > 0) {
 106             throw new RuntimeException("Premature mixed collections(s)");
 107         }
 108 
 109         // Verify that collections were done
 110         long collectionCount = collector.getCollectionCount();
 111         System.out.println(collectorName + ": collection count = "
 112                            + collectionCount);
 113         long collectionTime = collector.getCollectionTime();
 114         System.out.println(collectorName + ": collection time  = "
 115                            + collectionTime);
 116         if (collectionCount <= 0) {
 117             throw new RuntimeException("Collection count <= 0");
 118         }
 119         if (collectionTime <= 0) {
 120             throw new RuntimeException("Collector has not run");
 121         }
 122 
 123         gcProvoker.provokeMixedGC();
 124 
 125         usage = pool.getCollectionUsage().getUsed();
 126         System.out.println(poolName + ": usage after GC = " + usage);
 127         if (usage <= 0) {
 128             throw new RuntimeException(poolName + " found with zero usage");
 129         }
 130 
 131         long newCollectionCount = collector.getCollectionCount();
 132         System.out.println(collectorName + ": collection count = "
 133                            + newCollectionCount);
 134         long newCollectionTime = collector.getCollectionTime();
 135         System.out.println(collectorName + ": collection time  = "
 136                            + newCollectionTime);
 137         if (newCollectionCount <= collectionCount) {
 138             throw new RuntimeException("No new collection");
 139         }
 140         if (newCollectionTime <= collectionTime) {
 141             throw new RuntimeException("Collector has not run some more");
 142         }
 143 
 144         System.out.println("Test passed.");
 145     }
 146 
 147     /**
 148      * Utility class to guarantee a mixed GC. The class allocates several arrays and
 149      * promotes them to the oldgen. After that it tries to provoke mixed GC by
 150      * allocating new objects.
 151      *
 152      * The necessary condition for guaranteed mixed GC is running MixedGCProvoker is
 153      * running in VM with the following flags: -XX:MaxTenuringThreshold=1 -Xms12M
 154      * -Xmx12M -XX:G1MixedGCLiveThresholdPercent=100 -XX:G1HeapWastePercent=0
 155      * -XX:G1HeapRegionSize=1m
 156      */
 157     public class MixedGCProvoker {
 158         private final WhiteBox WB = WhiteBox.getWhiteBox();
 159         private final List<byte[]> liveOldObjects = new ArrayList<>();
 160         private final List<byte[]> newObjects = new ArrayList<>();
 161 
 162         public static final int ALLOCATION_SIZE = 20000;
 163         public static final int ALLOCATION_COUNT = 15;
 164 
 165         public void allocateOldObjects() {
 166             List<byte[]> deadOldObjects = new ArrayList<>();
 167             // Allocates buffer and promotes it to the old gen. Mix live and dead old
 168             // objects
 169             for (int i = 0; i < ALLOCATION_COUNT; ++i) {
 170                 liveOldObjects.add(new byte[ALLOCATION_SIZE * 5]);
 171                 deadOldObjects.add(new byte[ALLOCATION_SIZE * 5]);
 172             }
 173 
 174             // Do two young collections, MaxTenuringThreshold=1 will force promotion.
 175             // G1HeapRegionSize=1m guarantees that old gen regions will be filled.
 176             WB.youngGC();
 177             WB.youngGC();
 178             // Check it is promoted & keep alive
 179             Asserts.assertTrue(WB.isObjectInOldGen(liveOldObjects),
 180                                "List of the objects is suppose to be in OldGen");
 181             Asserts.assertTrue(WB.isObjectInOldGen(deadOldObjects),
 182                                "List of the objects is suppose to be in OldGen");
 183         }
 184 
 185         /**
 186          * Waits until Concurent Mark Cycle finishes
 187          * @param wb  Whitebox instance
 188          * @param sleepTime sleep time
 189          */
 190         private void waitTillCMCFinished(int sleepTime) {
 191             while (WB.g1InConcurrentMark()) {
 192                 if (sleepTime > -1) {
 193                     try {
 194                         Thread.sleep(sleepTime);
 195                     } catch (InterruptedException e) {
 196                         System.out.println("Got InterruptedException while waiting for ConcMarkCycle to finish");
 197                     }
 198                 }
 199             }
 200         }
 201 
 202         public void provokeMixedGC() {
 203             waitTillCMCFinished(0);
 204             WB.g1StartConcMarkCycle();
 205             waitTillCMCFinished(0);
 206             WB.youngGC();
 207 
 208             System.out.println("Allocating new objects to provoke mixed GC");
 209             // Provoke a mixed collection. G1MixedGCLiveThresholdPercent=100
 210             // guarantees that full old gen regions will be included.
 211             for (int i = 0; i < (ALLOCATION_COUNT * 20); i++) {
 212                 newObjects.add(new byte[ALLOCATION_SIZE]);
 213             }
 214             // check that liveOldObjects still alive
 215             Asserts.assertTrue(WB.isObjectInOldGen(liveOldObjects),
 216                                "List of the objects is suppose to be in OldGen");
 217         }
 218 
 219     }
 220 
 221 }