jdk-24/test/jdk/java/lang/Thread/virtual/stress/YieldALot.java

/*
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 * 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.
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 */

/*
 * @test
 * @summary Stress test Thread.yield
 * @requires vm.debug != true
 * @run main YieldALot 350000
 */

/*
 * @test
 * @requires vm.debug == true
 * @run main YieldALot 200000
 */

import java.time.Duration;
import java.util.concurrent.atomic.AtomicInteger;

public class YieldALot {

    public static void main(String[] args) throws Exception {
        int iterations = 1_000_000;
        if (args.length > 0) {
            iterations = Integer.parseInt(args[0]);
        }
        final int ITERATIONS = iterations;

        AtomicInteger count = new AtomicInteger();

        Thread thread = Thread.ofVirtual().start(() -> {
            while (count.incrementAndGet() < ITERATIONS) {
                Thread.yield();
            }
        });

        boolean terminated;
        do {
            terminated = thread.join(Duration.ofMillis(500));
            System.out.println(count.get());
        } while (!terminated);

        int countValue = count.get();
        if (countValue != ITERATIONS) {
            throw new RuntimeException("count = " + countValue);
        }
    }
}