133 lines
5.3 KiB
Java
133 lines
5.3 KiB
Java
/*
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* Copyright (c) 2020, 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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/*
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* @test HandshakeDirectTest
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* @bug 8240918
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* @summary This test tries to stress direct handshakes between threads while suspending them.
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* @library /testlibrary /test/lib
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* @build HandshakeDirectTest
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* @run main/othervm -XX:+UnlockDiagnosticVMOptions -XX:+UseBiasedLocking -XX:+SafepointALot -XX:BiasedLockingDecayTime=100000000 -XX:BiasedLockingBulkRebiasThreshold=1000000 -XX:BiasedLockingBulkRevokeThreshold=1000000 HandshakeDirectTest
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* @run main/othervm -XX:+UnlockDiagnosticVMOptions -XX:+UseBiasedLocking -XX:GuaranteedSafepointInterval=10 -XX:+HandshakeALot -XX:+SafepointALot -XX:BiasedLockingDecayTime=100000000 -XX:BiasedLockingBulkRebiasThreshold=1000000 -XX:BiasedLockingBulkRevokeThreshold=1000000 HandshakeDirectTest
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*/
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import java.util.concurrent.atomic.AtomicInteger;
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import java.util.concurrent.ThreadLocalRandom;
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import java.util.concurrent.Semaphore;
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import java.io.*;
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public class HandshakeDirectTest implements Runnable {
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static final int WORKING_THREADS = 32;
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static final int DIRECT_HANDSHAKES_MARK = 500000;
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static Thread[] workingThreads = new Thread[WORKING_THREADS];
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static Semaphore[] handshakeSem = new Semaphore[WORKING_THREADS];
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static Object[] locks = new Object[WORKING_THREADS];
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static boolean[] isBiased = new boolean[WORKING_THREADS];
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static AtomicInteger handshakeCount = new AtomicInteger(0);
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@Override
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public void run() {
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int me = Integer.parseInt(Thread.currentThread().getName());
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while (true) {
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try {
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if (!isBiased[me]) {
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handshakeSem[me].acquire();
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synchronized(locks[me]) {
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isBiased[me] = true;
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}
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handshakeSem[me].release();
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}
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// Handshake directly some other worker
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int handshakee = ThreadLocalRandom.current().nextInt(0, WORKING_THREADS - 1);
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if (handshakee == me) {
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// Pick another thread instead of me.
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handshakee = handshakee != 0 ? handshakee - 1 : handshakee + 1;
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}
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handshakeSem[handshakee].acquire();
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if (isBiased[handshakee]) {
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// Revoke biased lock
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synchronized(locks[handshakee]) {
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handshakeCount.incrementAndGet();
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}
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// Create new lock to be biased
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locks[handshakee] = new Object();
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isBiased[handshakee] = false;
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}
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handshakeSem[handshakee].release();
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if (handshakeCount.get() >= DIRECT_HANDSHAKES_MARK) {
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break;
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}
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} catch(InterruptedException ie) {
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throw new Error("Unexpected interrupt");
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}
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}
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}
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public static void main(String... args) throws Exception {
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HandshakeDirectTest test = new HandshakeDirectTest();
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// Initialize semaphores
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for (int i = 0; i < WORKING_THREADS; i++) {
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handshakeSem[i] = new Semaphore(1);
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}
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// Initialize locks
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for (int i = 0; i < WORKING_THREADS; i++) {
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locks[i] = new Object();
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}
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// Fire-up working threads.
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for (int i = 0; i < WORKING_THREADS; i++) {
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workingThreads[i] = new Thread(test, Integer.toString(i));
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workingThreads[i].start();
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}
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// Fire-up suspend-resume thread
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Thread suspendResumeThread = new Thread() {
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@Override
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public void run() {
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while (true) {
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int i = ThreadLocalRandom.current().nextInt(0, WORKING_THREADS - 1);
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workingThreads[i].suspend();
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try {
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Thread.sleep(1); // sleep for 1 ms
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} catch(InterruptedException ie) {
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}
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workingThreads[i].resume();
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}
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}
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};
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suspendResumeThread.setDaemon(true);
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suspendResumeThread.start();
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// Wait until the desired number of direct handshakes is reached
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// and check that all workers exited
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for (int i = 0; i < WORKING_THREADS; i++) {
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workingThreads[i].join();
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}
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}
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}
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