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/*
* Copyright (c) 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 id=default
* @bug 8335362
* @summary Test virtual thread usage with big stackChunks
* @requires vm.continuations
* @run junit/othervm BigStackChunk
*/
import java.util.concurrent.locks.ReentrantLock;
import org.junit.jupiter.api.Test;
import static org.junit.jupiter.api.Assertions.*;
class BigStackChunk {
void recurse(int cnt, ReentrantLock rlock) {
int i1 = cnt;
int i2 = i1 + 1;
int i3 = i2 + 1;
int i4 = i3 + 1;
int i5 = i4 + 1;
int i6 = i5 + 1;
int i7 = i6 + 1;
long ll = 2 * (long)i1;
float ff = ll + 1.2f;
double dd = ff + 1.3D;
if (cnt > 0) {
recurse(cnt - 1, rlock);
} else {
rlock.lock();
rlock.unlock();
}
}
@Test
void bigStackChunkTest() throws Exception {
int VTHREAD_CNT = Runtime.getRuntime().availableProcessors();
ReentrantLock rlock = new ReentrantLock();
Thread[] vthreads = new Thread[VTHREAD_CNT];
rlock.lock();
for (int i = 0; i < VTHREAD_CNT; i++) {
vthreads[i] = Thread.ofVirtual().start(() -> {
// Set up things so that half of the carriers will commit lots of
// pages in the stack while running the mounted vthread and half
// will just commit very few ones.
if (Math.random() < 0.5) {
recurse(300, rlock);
} else {
recurse(1, rlock);
}
});
}
await(vthreads[0], Thread.State.WAITING);
// Now we expect that some vthread that recursed a lot is mounted on
// a carrier that previously run a vthread that didn't recurse at all.
rlock.unlock();
for (int i = 0; i < VTHREAD_CNT; i++) {
vthreads[i].join();
}
}
private void await(Thread thread, Thread.State expectedState) throws InterruptedException {
Thread.State state = thread.getState();
while (state != expectedState) {
assertTrue(state != Thread.State.TERMINATED, "Thread has terminated");
Thread.sleep(10);
state = thread.getState();
}
}
}
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