1 /*

     2  * Copyright (c) 2013, 2018, 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.  Oracle designates this

     8  * particular file as subject to the "Classpath" exception as provided

     9  * by Oracle in the LICENSE file that accompanied this code.

    10  *

    11  * This code is distributed in the hope that it will be useful, but WITHOUT

    12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

    13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

    14  * version 2 for more details (a copy is included in the LICENSE file that

    15  * accompanied this code).

    16  *

    17  * You should have received a copy of the GNU General Public License version

    18  * 2 along with this work; if not, write to the Free Software Foundation,

    19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

    20  *

    21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

    22  * or visit www.oracle.com if you need additional information or have any

    23  * questions.

    24  */

    25 

    26 package jdk.test.lib.jfr;

    27 

    28 import jdk.test.lib.Asserts;

    29 

    30 public class RecurseThread extends Thread {

    31 

    32     public int totalDepth;

    33     public long dummy = 0; // Just to make sure the optimizer does not remove the test code.

    34     private volatile boolean timeToQuit = false;

    35     private volatile boolean isInRunLoop = false;

    36 

    37     public RecurseThread(int totalDepth) {

    38         this.totalDepth = totalDepth;

    39     }

    40 

    41     @Override

    42     public void run() {

    43         // totalDepth includes functions run() and recurse() and runloop().

    44         // Remove 3 from totalDepth when recursing.

    45         final int minDepth = 3;

    46         Asserts.assertGreaterThanOrEqual(totalDepth, minDepth, "totalDepth too small");

    47         int recurseDepth = totalDepth - minDepth;

    48 

    49         // We want the last function before runloop() to be recurseA().

    50         boolean startWithRecurseA = (totalDepth % 2) != 0;

    51         dummy = startWithRecurseA ? recurseA(recurseDepth) : recurseB(recurseDepth);

    52     }

    53 

    54     public void quit() {

    55         timeToQuit = true;

    56     }

    57 

    58     public boolean isInRunLoop() {

    59         return isInRunLoop;

    60     }

    61 

    62     private long recurseA(int depth) {

    63         if (depth == 0) {

    64             return recurseEnd();

    65         } else {

    66             return recurseB(depth - 1);

    67         }

    68     }

    69 

    70     private long recurseB(int depth) {

    71         if (depth == 0) {

    72             return recurseEnd();

    73         } else {

    74             return recurseA(depth - 1);

    75         }

    76     }

    77 

    78     // Test expects this function to be at the top of the stack.

    79     // We should not call other functions from here.

    80     private long recurseEnd() {

    81         isInRunLoop = true;

    82         long[] dummyTable = new long[] { 0, 2, 4, 8, 16 };

    83         long dummyTotal = 0;

    84         while (!timeToQuit) {

    85             dummyTotal = 0;

    86             for (int i = 0; i < 5; ++i) {

    87                 dummyTotal += dummyTable[i];

    88             }

    89         }

    90         return dummyTotal;

    91     }

    92 

    93 }