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
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
|
/*
* Copyright (c) 2023, 2024, 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
* @bug 8322818
* @summary Stress test Thread.getStackTrace on a virtual thread that is pinned
* @requires vm.debug != true
* @modules jdk.management
* @library /test/lib
* @run main/othervm/timeout=300 --enable-native-access=ALL-UNNAMED GetStackTraceALotWhenPinned 100000
*/
/*
* @test
* @requires vm.debug == true
* @modules jdk.management
* @library /test/lib
* @run main/othervm/timeout=300 --enable-native-access=ALL-UNNAMED GetStackTraceALotWhenPinned 50000
*/
import java.time.Instant;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.concurrent.locks.LockSupport;
import jdk.test.lib.Platform;
import jdk.test.lib.thread.VThreadRunner; // ensureParallelism requires jdk.management
import jdk.test.lib.thread.VThreadPinner;
public class GetStackTraceALotWhenPinned {
public static void main(String[] args) throws Exception {
// need at least two carrier threads when main thread is a virtual thread
if (Thread.currentThread().isVirtual()) {
VThreadRunner.ensureParallelism(2);
}
int iterations;
int value = Integer.parseInt(args[0]);
if (Platform.isOSX() && Platform.isX64()) {
// reduced iterations on macosx-x64
iterations = Math.max(value / 4, 1);
} else {
iterations = value;
}
var barrier = new Barrier(2);
// Start a virtual thread that loops doing Thread.yield and parking while pinned.
// This loop creates the conditions for the main thread to sample the stack trace
// as it transitions from being unmounted to parking while pinned.
var thread = Thread.startVirtualThread(() -> {
boolean timed = false;
for (int i = 0; i < iterations; i++) {
// wait for main thread to arrive
barrier.await();
Thread.yield();
boolean b = timed;
VThreadPinner.runPinned(() -> {
if (b) {
LockSupport.parkNanos(Long.MAX_VALUE);
} else {
LockSupport.park();
}
});
timed = !timed;
}
});
long lastTime = System.nanoTime();
for (int i = 1; i <= iterations; i++) {
// wait for virtual thread to arrive
barrier.await();
thread.getStackTrace();
LockSupport.unpark(thread);
long currentTime = System.nanoTime();
if (i == iterations || ((currentTime - lastTime) > 1_000_000_000L)) {
System.out.format("%s => %d of %d%n", Instant.now(), i, iterations);
lastTime = currentTime;
}
if (Thread.currentThread().isInterrupted()) {
// fail quickly if interrupted by jtreg
throw new RuntimeException("interrupted");
}
}
}
/**
* Alow threads wait for each other to reach a common barrier point. This class does
* not park threads that are waiting for the barrier to trip, instead it spins. This
* makes it suitable for tests that use LockSupport.park or Thread.yield.
*/
private static class Barrier {
private final int parties;
private final AtomicInteger count;
private volatile int generation;
Barrier(int parties) {
this.parties = parties;
this.count = new AtomicInteger(parties);
}
void await() {
int g = generation;
if (count.decrementAndGet() == 0) {
count.set(parties);
generation = g + 1;
} else {
while (generation == g) {
Thread.onSpinWait();
}
}
}
}
}
|
