126 lines
3.9 KiB
Java
126 lines
3.9 KiB
Java
/*
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* Copyright (c) 2020, 2024, Oracle and/or its affiliates. All rights reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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* or visit www.oracle.com if you need additional information or have any
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* questions.
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*/
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/**
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* @test
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* @summary Stress test that reaches the process limit for thread count, or time limit.
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* @requires os.family != "aix"
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* @key stress
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* @run main/othervm -Xmx1g ThreadCountLimit
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*/
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/**
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* @test
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* @summary Stress test that reaches the process limit for thread count, or time limit.
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* @requires os.family == "aix"
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* @key stress
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* @run main/othervm -Xmx1g -XX:MaxExpectedDataSegmentSize=16g ThreadCountLimit
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*/
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import java.util.concurrent.CountDownLatch;
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import java.util.ArrayList;
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public class ThreadCountLimit {
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static final int TIME_LIMIT_MS = 5000; // Create as many threads as possible in 5 sec
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static class Worker extends Thread {
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private final CountDownLatch startSignal;
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Worker(CountDownLatch startSignal) {
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this.startSignal = startSignal;
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}
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@Override
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public void run() {
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try {
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startSignal.await();
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} catch (InterruptedException e) {
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throw new Error("Unexpected", e);
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}
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}
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}
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public static void main(String[] args) {
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CountDownLatch startSignal = new CountDownLatch(1);
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ArrayList<Worker> workers = new ArrayList<Worker>();
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boolean reachedTimeLimit = false;
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boolean reachedNativeOOM = false;
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int countAtTimeLimit = -1;
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int countAtNativeOOM = -1;
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// This is dangerous loop: it depletes system resources,
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// so doing additional things there that may end up allocating
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// Java/native memory risks failing the VM prematurely.
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// Avoid doing unnecessary calls, printouts, etc.
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int count = 1;
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long start = System.currentTimeMillis();
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try {
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while (true) {
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Worker w = new Worker(startSignal);
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w.start();
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workers.add(w);
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count++;
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long end = System.currentTimeMillis();
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if ((end - start) > TIME_LIMIT_MS) {
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reachedTimeLimit = true;
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countAtTimeLimit = count;
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break;
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}
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}
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} catch (OutOfMemoryError e) {
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if (e.getMessage().contains("unable to create native thread")) {
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// Linux, macOS path
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reachedNativeOOM = true;
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countAtNativeOOM = count;
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} else {
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throw e;
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}
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}
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startSignal.countDown();
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try {
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for (Worker w : workers) {
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w.join();
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}
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} catch (InterruptedException e) {
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throw new Error("Unexpected", e);
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}
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// Now that all threads have joined, we are away from dangerous
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// VM state and have enough memory to perform any other things.
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if (reachedTimeLimit) {
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// Windows path or a system with very large ulimit
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System.out.println("INFO: reached the time limit " + TIME_LIMIT_MS +
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" ms, with " + countAtTimeLimit + " threads created");
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} else if (reachedNativeOOM) {
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System.out.println("INFO: reached this process thread count limit with " +
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countAtNativeOOM + " threads created");
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}
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}
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}
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