1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
|
/*
* Copyright (c) 2002, 2020, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
/*
* @test
*
* @summary converted from VM Testbase gc/memory/Array/SampleMe.
* VM Testbase keywords: [gc]
* VM Testbase readme:
* ## This test is a basic implementation of the thoughts below.
* Create an object: Cell
* which contains an array of bytes, the size of
* which is determined in the ctor call
* You could then have varying sizes of these objects.
* You could then store them in an array. Then delete
* a subset and garbage collect:
* Basically, you are looking at the holes and the
* remaining cells, their numbers and their locations:
* small/medium/large sized chunks
* small/medium/large sized holes
* contiguous/mixed/discontiguous
* none, few, some, many, all
* The key here is to provide a broad spectrum of
* various GC scenarios. eventually, you will want
* to take into account generational effects by making
* sure that various portions of the chunks and holes
* are created before or after certain generational
* boundaries (1 Megabyte of allocs, for example).
*
* @library /vmTestbase
* /test/lib
* @run main/othervm gc.memory.Array.SampleMe.SampleMe
*/
package gc.memory.Array.SampleMe;
//SampleMe.java
// import SampleClass;
public class SampleMe
{
public static void main(String args[])
{
int arraySize = 2000;
long before;
long after;
SampleClass array[] = new SampleClass[arraySize];
for (int i= 0; i < arraySize; i++)
{
array[i] = new SampleClass();
if ((i % (arraySize / 10)) == 0)
{
System.out.println(i);
}
}
System.gc();
System.out.println("Erasing objects");
for (int i = 0; i < arraySize /2; i ++)
{
array[i*2] = null;
}
System.out.println("ready to GC");
before = System.currentTimeMillis();
System.gc();
after = System.currentTimeMillis();
System.out.println(after - before);
for (int i = 0; i < arraySize /3; i ++)
{
array[i*2 + 1] = null;
}
before = System.currentTimeMillis();
System.gc();
after = System.currentTimeMillis();
System.out.println(after - before);
for (int i = 0; i < arraySize; i ++)
{
array[i] = null;
}
}
}
|
