1 /*
2 * Copyright (c) 2024, 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.
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 /*
25 * @test
26 * @summary Stress test virtual threads with a variation of the Skynet 1M benchmark that uses
27 * a channel implementation based on object monitors. This variant uses a reduced number of
28 * 100k virtual threads at the final level.
29 * @requires vm.debug != true & vm.continuations
30 * @run main/othervm/timeout=300 Skynet100kWithMonitors 50
31 */
32
33 /*
34 * @test
35 * @requires vm.debug == true & vm.continuations
36 * @run main/othervm/timeout=300 Skynet100kWithMonitors 10
37 */
38
39 public class Skynet100kWithMonitors {
40
41 public static void main(String[] args) {
42 int iterations = (args.length) > 0 ? Integer.parseInt(args[0]) : 10;
43 for (int i = 0; i < iterations; i++) {
44 skynet(100_000, 4999950000L);
45 }
46 }
47
48 static void skynet(int num, long expected) {
49 long start = System.currentTimeMillis();
50 var chan = new Channel<Long>();
51
52 Thread.startVirtualThread(() -> skynet(chan, 0, num, 10));
53
54 long sum = chan.receive();
55 long end = System.currentTimeMillis();
56 System.out.format("Result: %d in %s ms%n", sum, (end-start));
57 if (sum != expected)
58 throw new RuntimeException("Expected " + expected);
59 }
60
61 static void skynet(Channel<Long> result, int num, int size, int div) {
62 if (size == 1) {
63 result.send((long)num);
64 } else {
65 var chan = new Channel<Long>();
66 for (int i = 0; i < div; i++) {
67 int subNum = num + i * (size / div);
68 Thread.startVirtualThread(() -> skynet(chan, subNum, size / div, div));
69 }
70 long sum = 0;
71 for (int i = 0; i < div; i++) {
72 sum += chan.receive();
73 }
74 result.send(sum);
75 }
76 }
77
78 static class Channel<T> {
79 private final Object lock = new Object();
80 private T element;
81
82 Channel() {
83 }
84
85 void send(T e) {
86 boolean interrupted = false;
87 synchronized (lock) {
88 while (element != null) {
89 try {
90 lock.wait();
91 } catch (InterruptedException x) {
92 interrupted = true;
93 }
94 }
95 element = e;
96 lock.notifyAll();
97 }
98 if (interrupted)
99 Thread.currentThread().interrupt();
100 }
101
102 T receive() {
103 T e;
104 boolean interrupted = false;
105 synchronized (lock) {
106 while ((e = element) == null) {
107 try {
108 lock.wait();
109 } catch (InterruptedException x) {
110 interrupted = true;
111 }
112 }
113 element = null;
114 lock.notifyAll();
115 }
116 if (interrupted)
117 Thread.currentThread().interrupt();
118 return e;
119 }
120 }
121 }