| /* |
| * Copyright (c) 2009, 2010, 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 6823609 |
| * @summary Selector.select can hangs on Windows for cases where a helper thread |
| * becomes redudant but a new helper is immediately needed. |
| */ |
| |
| import java.nio.channels.*; |
| import java.io.IOException; |
| |
| public class HelperSlowToDie { |
| private static final int CHANNELS_PER_THREAD = 1023; |
| private static final int TEST_ITERATIONS = 200; |
| private static volatile boolean done; |
| |
| public static void main(String[] args) throws IOException { |
| if (!System.getProperty("os.name").startsWith("Windows")) { |
| System.out.println("Test skipped as it verifies a Windows specific bug"); |
| return; |
| } |
| |
| Selector sel = Selector.open(); |
| |
| // register channels |
| SocketChannel[] channels = new SocketChannel[CHANNELS_PER_THREAD]; |
| for (int i=0; i<CHANNELS_PER_THREAD; i++) { |
| SocketChannel sc = SocketChannel.open(); |
| sc.configureBlocking(false); |
| sc.register(sel, SelectionKey.OP_CONNECT); |
| channels[i] = sc; |
| } |
| sel.selectNow(); |
| |
| // Start threads to swamp all cores but one. This improves the chances |
| // of duplicating the bug. |
| Runnable busy = new Runnable() { |
| public void run() { |
| while (!done) ; // no nothing |
| } |
| }; |
| int ncores = Runtime.getRuntime().availableProcessors(); |
| for (int i=0; i<ncores-1; i++) |
| new Thread(busy).start(); |
| |
| // Loop changing the number of channels from 1023 to 1024 and back. |
| for (int i=0; i<TEST_ITERATIONS; i++) { |
| SocketChannel sc = SocketChannel.open(); |
| sc.configureBlocking(false); |
| sc.register(sel, SelectionKey.OP_CONNECT); |
| sel.selectNow(); // cause helper to spin up |
| sc.close(); |
| sel.selectNow(); // cause helper to retire |
| } |
| |
| // terminate busy threads |
| done = true; |
| |
| // clean-up |
| for (int i=0; i<CHANNELS_PER_THREAD; i++) { |
| channels[i].close(); |
| } |
| sel.close(); |
| } |
| } |