jdk-24/test/jdk/java/util/concurrent/forkjoin/Starvation.java
Doug Lea 789f704d9a 8322732: ForkJoinPool may underutilize cores in async mode
8327854: Test java/util/stream/test/org/openjdk/tests/java/util/stream/WhileOpStatefulTest.java failed with RuntimeException

Reviewed-by: alanb
2024-06-05 13:02:15 +00:00

57 lines
2.1 KiB
Java

/*
* Copyright (c) 2004, 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
* @bug 8322732
* @summary ForkJoinPool utilizes available workers even with arbitrary task dependencies
*/
import java.util.concurrent.Callable;
import java.util.concurrent.ForkJoinPool;
import java.util.concurrent.atomic.AtomicInteger;
public class Starvation {
static final AtomicInteger count = new AtomicInteger();
static final Callable<Void> noop = new Callable<Void>() {
public Void call() {
return null; }};
static final class AwaitCount implements Callable<Void> {
private int c;
AwaitCount(int c) { this.c = c; }
public Void call() {
while (count.get() == c) Thread.onSpinWait();
return null; }};
public static void main(String[] args) throws Exception {
try (var pool = new ForkJoinPool(2)) {
for (int i = 0; i < 100_000; i++) {
var future1 = pool.submit(new AwaitCount(i));
var future2 = pool.submit(noop);
future2.get();
count.set(i + 1);
future1.get();
}
}
}
}