1 /*
   2  * Copyright (c) 2018, 2019, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  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).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  */
  23 
  24 package gc.g1;
  25 
  26 /**
  27  * @test TestPeriodicCollection
  28  * @requires vm.gc.G1
  29  * @requires vm.compMode != "Xcomp"
  30  * @summary Verify that heap shrinks when the application is idle.
  31  * @library /test/lib /
  32  * @modules java.base/jdk.internal.misc
  33  * @modules java.management/sun.management
  34  * @run main/othervm -XX:MaxNewSize=32M -XX:InitialHeapSize=48M -Xmx128M -XX:MinHeapFreeRatio=5 -XX:MaxHeapFreeRatio=25 -XX:+UseG1GC -XX:G1PeriodicGCInterval=3000 -XX:+G1PeriodicGCInvokesConcurrent -Xlog:gc,gc+periodic=debug,gc+ergo+heap=debug gc.g1.TestPeriodicCollection
  35  * @run main/othervm -XX:MaxNewSize=32M -XX:InitialHeapSize=48M -Xmx128M -XX:MinHeapFreeRatio=5 -XX:MaxHeapFreeRatio=25 -XX:+UseG1GC -XX:G1PeriodicGCInterval=3000 -XX:-G1PeriodicGCInvokesConcurrent -Xlog:gc,gc+periodic=debug,gc+ergo+heap=debug gc.g1.TestPeriodicCollection
  36  */
  37 
  38 import com.sun.management.HotSpotDiagnosticMXBean;
  39 
  40 import gc.testlibrary.Helpers;
  41 
  42 import java.lang.management.GarbageCollectorMXBean;
  43 import java.lang.management.ManagementFactory;
  44 import java.lang.management.MemoryUsage;
  45 import java.text.NumberFormat;
  46 import static jdk.test.lib.Asserts.*;
  47 
  48 public class TestPeriodicCollection {
  49 
  50     public static final String MIN_FREE_RATIO_FLAG_NAME = "MinHeapFreeRatio";
  51     public static final String MAX_FREE_RATIO_FLAG_NAME = "MaxHeapFreeRatio";
  52 
  53     private static final int IDLE_TIME = 7 * 1000;
  54 
  55     private static boolean gcOccurred() {
  56         for (GarbageCollectorMXBean b : ManagementFactory.getGarbageCollectorMXBeans()) {
  57             if (b.getCollectionCount() != 0) {
  58                 return true;
  59             }
  60         }
  61         return false;
  62     }
  63 
  64     public static void main(String[] args) {
  65         MemoryUsage muInitial = ManagementFactory.getMemoryMXBean().getHeapMemoryUsage();
  66         printMemoryUsage("initial", muInitial);
  67 
  68         if (gcOccurred()) {
  69           System.out.println("At least one garbage collection occurred. Exiting as this may have already shrunk the heap.");
  70           return;
  71         }
  72 
  73         try {
  74             Thread.sleep(IDLE_TIME);
  75         } catch (InterruptedException ie) {
  76             System.err.println("Skipped. Failed to wait for idle collection");
  77         }
  78 
  79         MemoryUsage muAfter = ManagementFactory.getMemoryMXBean().getHeapMemoryUsage();
  80         printMemoryUsage("after", muAfter);
  81 
  82         assertLessThan(muAfter.getCommitted(), muInitial.getCommitted(), String.format(
  83                 "committed free heap size is not less than committed full heap size, heap hasn't been shrunk?%n"
  84                 + "%s = %s%n%s = %s",
  85                 MIN_FREE_RATIO_FLAG_NAME,
  86                 ManagementFactory.getPlatformMXBean(HotSpotDiagnosticMXBean.class)
  87                     .getVMOption(MIN_FREE_RATIO_FLAG_NAME).getValue(),
  88                 MAX_FREE_RATIO_FLAG_NAME,
  89                 ManagementFactory.getPlatformMXBean(HotSpotDiagnosticMXBean.class)
  90                     .getVMOption(MAX_FREE_RATIO_FLAG_NAME).getValue()
  91         ));
  92     }
  93 
  94     public static final NumberFormat NF = Helpers.numberFormatter();
  95 
  96     public static void printMemoryUsage(String label, MemoryUsage memusage) {
  97         float freeratio = 1f - (float) memusage.getUsed() / memusage.getCommitted();
  98         System.out.format("[%-24s] init: %-7s, used: %-7s, comm: %-7s, freeRatio ~= %.1f%%%n",
  99                 label,
 100                 NF.format(memusage.getInit()),
 101                 NF.format(memusage.getUsed()),
 102                 NF.format(memusage.getCommitted()),
 103                 freeratio * 100
 104         );
 105     }
 106 }