1 /*
 2  * Copyright (c) 2020, 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 Thread.yield
27  * @requires vm.debug != true
28  * @run main YieldALot 500000
29  */
30 
31 /*
32  * @test
33  * @requires vm.debug == true
34  * @run main YieldALot 200000
35  */
36 
37 import java.time.Duration;
38 import java.time.Instant;
39 import java.util.concurrent.atomic.AtomicInteger;
40 
41 public class YieldALot {
42 
43     public static void main(String[] args) throws Exception {
44         int iterations;
45         if (args.length > 0) {
46             iterations = Integer.parseInt(args[0]);
47         } else {
48             iterations = 1_000_000;
49         }
50 
51         AtomicInteger count = new AtomicInteger();
52         Thread thread = Thread.ofVirtual().start(() -> {
53             while (count.incrementAndGet() < iterations) {
54                 Thread.yield();
55             }
56         });
57 
58         boolean terminated;
59         do {
60             terminated = thread.join(Duration.ofSeconds(1));
61             System.out.println(Instant.now() + " => " + count.get() + " of " + iterations);
62         } while (!terminated);
63 
64         int countValue = count.get();
65         if (countValue != iterations) {
66             throw new RuntimeException("Thread terminated, count=" + countValue);
67         }
68     }
69 }