1 /*
   2  * Copyright (c) 2017, Google 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 MyPackage;
  25 
  26 import java.util.List;
  27 
  28 /**
  29  * @test
  30  * @summary Checks the frequent garbage storage system.
  31  * @build Frame HeapMonitor
  32  * @compile HeapMonitorFrequentTest.java
  33  * @run main/othervm/native -agentlib:HeapMonitor MyPackage.HeapMonitorFrequentTest
  34  */
  35 
  36 public class HeapMonitorFrequentTest {
  37 
  38   private native static boolean framesExistInFrequent(Frame[] frames);
  39 
  40   private static List<Frame> runner(int max) {
  41     List<Frame> frameList = null;
  42     for (int j = 0; j < max; j++) {
  43       frameList = HeapMonitor.allocate();
  44     }
  45     frameList.add(new Frame("runner", "(I)Ljava/util/List;", "HeapMonitorFrequentTest.java", 43));
  46     return frameList;
  47   }
  48 
  49   public static void main(String[] args) {
  50     HeapMonitor.enableSampling();
  51     // We are testing for the recent garbage sampler:
  52     // First run for 10 iterations to fill up the garbage sampler.
  53     List<Frame> firstFrameList = runner(10);
  54     firstFrameList.add(new Frame("main", "([Ljava/lang/String;)V", "HeapMonitorFrequentTest.java",
  55           53));
  56 
  57     // Now because we are in a different stack frame line here, we can just re-use the same runner.
  58     // Run for 10, this would normally replace the garbage history but frequent has a back-off
  59     // mechanism making it less and less likely to populate the history buffer.
  60     // See the HeapMonitorRecentTest to understand the Frequent variation.
  61     List<Frame> secondFrameList = runner(10);
  62     secondFrameList.add(new Frame("main", "([Ljava/lang/String;)V", "HeapMonitorFrequentTest.java",
  63           61));
  64 
  65     // Both types should exist in frequent since it was frequent enough.
  66     boolean status = framesExistInFrequent(firstFrameList.toArray(new Frame[0]));
  67     if (!status) {
  68       throw new RuntimeException("Old frames no longer exist in the frequent list.");
  69     }
  70 
  71     status = framesExistInFrequent(secondFrameList.toArray(new Frame[0]));
  72     if (!status) {
  73       throw new RuntimeException("New frames no longer exist in the frequent list");
  74     }
  75   }
  76 }