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 /**
  27  * @test
  28  * @summary Verifies the JVMTI Heap Monitor stack depth handling.
  29  * @build Frame HeapMonitor
  30  * @compile HeapMonitorStackDepthTest.java
  31  * @run main/othervm/native -agentlib:HeapMonitor MyPackage.HeapMonitorStackDepthTest
  32  */
  33 
  34 public class HeapMonitorStackDepthTest {
  35   private native static double getAverageStackDepth();
  36 
  37   private static double calculateErrorPercentage(double expected, double actual) {
  38     double error = expected - actual;
  39     error = error < 0 ? -error : error;
  40     return error / expected * 100;
  41   }
  42 
  43   private static void runner(int max, int depth) {
  44     for (int j = 0; j < max; j++) {
  45       HeapMonitor.allocate(depth);
  46     }
  47   }
  48 
  49   public static void main(String[] args) {
  50     int[] depths = {10, 100, 500};
  51 
  52     for (int depthIdx = 0; depthIdx < depths.length; depthIdx++) {
  53       int depth = depths[depthIdx];
  54 
  55       HeapMonitor.enableSampling();
  56       // Do the runner 10 times to ensure the stack is really sampled.
  57       runner(10, depth);
  58 
  59       // baseDepth represents the helper method depth: main, runner, HeapMonitor.allocate,
  60       // and HeapMonitor.actuallyAllocate.
  61       // To get the requested depth, remove this from the count.
  62       final int baseDepth = 4;
  63       double averageDepth = getAverageStackDepth() - baseDepth;
  64       double errorPercentage = calculateErrorPercentage(depth, averageDepth);
  65 
  66       // 3% error should be close enough.
  67       if (errorPercentage > 3) {
  68         throw new RuntimeException("Stack depth average over 5% for depth " + depth + " : " + averageDepth + " , error: " + errorPercentage);
  69       }
  70 
  71       HeapMonitor.disableSampling();
  72     }
  73 
  74 
  75     // Last test is 1024, which is the current maximum.
  76     HeapMonitor.enableSampling();
  77     final int maximumDepth = 1024;
  78     // Do the runner 10 times to ensure the stack is really sampled.
  79     runner(10, maximumDepth);
  80     // Because of the extra frames, we should be at (maximumDepth + a few frames). Due to the
  81     // maximum depth allowed, we hit it and so should still be at an average of 1024.
  82     double averageDepth = getAverageStackDepth();
  83     double errorPercentage = calculateErrorPercentage(maximumDepth, averageDepth);
  84     HeapMonitor.disableSampling();
  85 
  86     // 3% error should be close enough.
  87     if (errorPercentage > 3) {
  88       throw new RuntimeException("Stack depth average over 5% for depth 1024 : " + averageDepth + " , error: " + errorPercentage);
  89     }
  90   }
  91 }