Name: szC45993 Date: 03/26/99



The Tonga/src/nsk/arguments/args00106 (source are placed below),
demonstrates that some debugging options can hang java_g (HotSpot VM 1.0rc2,
mixed mode, debug build C). See also 4223429 bug report.

cd D:/args00106
export CLASSPATH="D:/args00106"
$ c:/jdk1.2.ZSS02/bin/java_g -version
java version "1.2"
HotSpot VM (1.0rc2, mixed mode, debug build C)
[Verifying threads permgen oldgen ct newgen rset syms lkup zone dict hand C-heap ]
$ c:/Jdk1.2.ZSS02/bin/java_g -verify args00106
0: 3536304
1: 3516616
2: 3497008
3: 3477400
4: 3457792
Test passed.
[Verifying threads permgen oldgen ct newgen rset syms lkup zone dict hand C-heap ]
$

However, if test is started with -Xprof flag then after about 14:00 CTU
Time (Pentium II, 350Mhz, RAM 128Mb) the test hangs HS java_g, for
example, with the following last output fragment:


$ c:/Jdk1.2.ZSS02/bin/java_g -verify -Xprof args00106

...

Thread::resume_async 0x7d3648 [b6] main (prio: 5)
Thread::suspend_async 0x7d3648 [b6] main (prio: 5)
Thread::resume_async 0x7d3648 [b6] main (prio: 5)
Thread::suspend_async 0x7d3648 [b6] main (prio: 5)
Thread::resume_async 0x7d3648 [b6] main (prio: 5)
100908: Handle allocated: 0x849a010
Thread::suspend_async 0x7d3648 [b6] main (prio: 5)
Thread::resume_async 0x7d3648 [b6] main (prio: 5)
100909: Handle allocated: 0xc5413d8
Thread::suspend_100910: Handle async 0x7d3648 [b6] main (prio: 5)
Thread::resume_async 0x7d3648 [b6] main (prio: 5)
allocated: 0x849a010
100911: Handle allocated: 0x849a010
100912: Handle allocated: 0xcT5h4r1e3add8:
:s1u0s0p9e1n3d:_ aHsaynndcl e0 xa7ldl3o6c4a8t e[db:6 ]0 xm8a4i9na 0(1p0r
ioH:e a5p)
m




SOURCE:
========

//--------------------- args00106.java:
//args00106.java
/* This test simply creates a series of circularly
 * linked memeory objects which should be able to be
 * GC'd
 */


class MemoryObject
{
    byte array[];
    MemoryObject next;
    MemoryObject previous;

    public MemoryObject(int size)
    {
        array = new byte[size];
    }
}

class args00106
{
    static final int ARRAY_SIZE = 100;
    static final int OBJECT_SIZE = 10;
    static final int LOOP_COUNT = 5;
    static final int CIRCULARITY_SIZE = 3;

    static MemoryObject memoryArray[] = new MemoryObject[ARRAY_SIZE];

    public static void main(String args[])
    {
        for (int j = 0; j < LOOP_COUNT; j++)
        {
            System.out.println(j + ": " + Runtime.getRuntime().freeMemory());
            for (int i = 0; i < ARRAY_SIZE; i ++)
            {
                memoryArray[i] = new MemoryObject(OBJECT_SIZE);
                makeCircular(memoryArray[i], CIRCULARITY_SIZE);
            }
        }

        // if there's any memory left, let's assume it's okay
        System.out.println("Test passed.");

    }

    public static void makeCircular(MemoryObject mObj, int depth)
    {
MemoryObject tmpObj = mObj;

        for (int i = 0; i < depth; i++)
        {
            tmpObj.next = new MemoryObject(OBJECT_SIZE);
            tmpObj= tmpObj.next;
        }
tmpObj.next = mObj;
    }

    public static void confirmCircular(MemoryObject mObj)
    {
int count = 0;
MemoryObject mObj2 = mObj;
while (mObj2.next != mObj)
{
count++;
mObj2 = mObj2.next;
}
System.out.println("Circularity level: " + count);
    }
}
//---------------------

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