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/*
* 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
* @summary Stress test Thread.getStackTrace on virtual threads that are blocking or
* blocked on monitorenter
* @requires vm.debug != true
* @modules jdk.management
* @library /test/lib
* @run main/othervm/timeout=300 GetStackTraceALotWhenBlocking 100000
*/
/*
* @test
* @requires vm.debug == true & vm.continuations
* @modules jdk.management
* @library /test/lib
* @run main/othervm/timeout=300 GetStackTraceALotWhenBlocking 50000
*/
import java.time.Instant;
import java.util.concurrent.ThreadLocalRandom;
import java.util.concurrent.atomic.AtomicBoolean;
import jdk.test.lib.Platform;
import jdk.test.lib.thread.VThreadRunner; // ensureParallelism requires jdk.management
public class GetStackTraceALotWhenBlocking {
public static void main(String[] args) throws Exception {
// need at least two carriers
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 done = new AtomicBoolean();
var lock = new Object();
Runnable task = () -> {
long count = 0L;
while (!done.get()) {
synchronized (lock) {
pause();
}
count++;
}
System.out.format("%s %s => %d loops%n", Instant.now(), Thread.currentThread(), count);
};
var thread1 = Thread.ofVirtual().start(task);
var thread2 = Thread.ofVirtual().start(task);
long lastTime = System.nanoTime();
try {
for (int i = 1; i <= iterations; i++) {
thread1.getStackTrace();
pause();
thread2.getStackTrace();
pause();
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");
}
}
} finally {
done.set(true);
thread1.join();
thread2.join();
}
}
private static void pause() {
if (ThreadLocalRandom.current().nextBoolean()) {
Thread.onSpinWait();
} else {
Thread.yield();
}
}
}
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