1 /*
2 * Copyright (c) 2022, 2023, 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
27 * @requires vm.continuations
28 * @run main/othervm/timeout=300 -Xmx1g Skynet
29 */
30
31 /*
32 * @test
33 * @requires vm.debug == true & vm.continuations
34 * @requires vm.gc.Z
35 * @run main/othervm/timeout=300 -XX:+UnlockDiagnosticVMOptions
36 * -XX:+ZVerifyOops -XX:ZCollectionInterval=0.01 -Xmx1g Skynet
37 */
38
39 import java.util.concurrent.BlockingQueue;
40 import java.util.concurrent.SynchronousQueue;
41 import java.util.concurrent.ThreadFactory;
42
43 public class Skynet {
44 public static void main(String[] args) {
45 int iterations = (args.length > 0) ? Integer.parseInt(args[0]) : 10;
46 for (int i = 0; i < iterations; i++) {
47 skynet(1_000_000, 499999500000L);
48 }
49 }
50
51 static void skynet(int num, long expected) {
52 long start = System.currentTimeMillis();
53 var chan = new Channel<Long>();
54
55 Thread.startVirtualThread(() -> skynet(chan, 0, num, 10));
56
57 long sum = chan.receive();
58 long end = System.currentTimeMillis();
59 System.out.format("Result: %d in %s ms%n", sum, (end-start));
60 if (sum != expected)
61 throw new AssertionError("unexpected result!");
62 }
63
64 static void skynet(Channel<Long> result, int num, int size, int div) {
65 if (size == 1) {
66 result.send((long)num);
67 } else {
68 var chan = new Channel<Long>();
69 for (int i = 0; i < div; i++) {
70 int subNum = num + i * (size / div);
71 Thread.startVirtualThread(() -> skynet(chan, subNum, size / div, div));
72 }
73 long sum = 0;
74 for (int i = 0; i < div; i++) {
75 sum += chan.receive();
76 }
77 result.send(sum);
78 }
79 }
80
81 static class Channel<T> {
82 private final BlockingQueue<T> q;
83
84 Channel() {
85 q = new SynchronousQueue<>();
86 }
87
88 void send(T e) {
89 boolean interrupted = false;
90 while (true) {
91 try {
92 q.put(e);
93 break;
94 } catch (InterruptedException x) {
95 interrupted = true;
96 }
97 }
98 if (interrupted)
99 Thread.currentThread().interrupt();
100 }
101
102 T receive() {
103 boolean interrupted = false;
104 T e;
105 while (true) {
106 try {
107 e = q.take();
108 break;
109 } catch (InterruptedException x) {
110 interrupted = true;
111 }
112 }
113 if (interrupted)
114 Thread.currentThread().interrupt();
115 return e;
116 }
117 }
118 }