3789983e89
Reviewed-by: darcy, ihse
136 lines
5.4 KiB
Java
136 lines
5.4 KiB
Java
/*
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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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* This file is available under and governed by the GNU General Public
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* License version 2 only, as published by the Free Software Foundation.
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* However, the following notice accompanied the original version of this
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* file:
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*
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* Written by Doug Lea with assistance from members of JCP JSR-166
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* Expert Group and released to the public domain, as explained at
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* http://creativecommons.org/publicdomain/zero/1.0/
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*/
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/*
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* @test
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* @bug 8008378
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* @summary Basic checks for parallelism 0, and null returning factory
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* @run main/othervm -Djava.util.concurrent.ForkJoinPool.common.parallelism=0 ThreadLessCommon
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* @run main/othervm -Djava.util.concurrent.ForkJoinPool.common.threadFactory=ThreadLessCommon$NullForkJoinWorkerThreadFactory ThreadLessCommon
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* @author Chris Hegarty
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*/
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import java.util.concurrent.ForkJoinPool;
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import java.util.concurrent.ForkJoinPool.ForkJoinWorkerThreadFactory;
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import java.util.concurrent.ForkJoinWorkerThread;
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import java.util.concurrent.RecursiveTask;
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public class ThreadLessCommon {
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static final int THRESHOLD = 1000;
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static final boolean debug = true;
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private static void realMain(String[] args) throws Throwable {
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if (debug) {
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String pp = System.getProperty(
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"java.util.concurrent.ForkJoinPool.common.parallelism");
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System.out.println(
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"java.util.concurrent.ForkJoinPool.common.parallelism:" + pp);
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String tf = System.getProperty(
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"java.util.concurrent.ForkJoinPool.common.threadFactory");
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System.out.println(
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"java.util.concurrent.ForkJoinPool.common.threadFactory:" + tf);
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}
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long from = 0, to = 50000;
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RecursiveTask<Long> task = new SumTask(from, to, Thread.currentThread());
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long sum = task.invoke();
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System.out.printf("%nSum: from [%d] to [%d] = [%d]%n", from, to, sum);
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task.fork();
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sum = task.join();
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System.out.printf("%nSum: from [%d] to [%d] = [%d]%n", from, to, sum);
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sum = ForkJoinPool.commonPool().invoke(task.fork());
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System.out.printf("%nSum: from [%d] to [%d] = [%d]%n", from, to, sum);
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}
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static class SumTask extends RecursiveTask<Long> {
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final Thread expectedThread;
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final long from;
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final long to;
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SumTask(long from, long to, Thread thread) {
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this.from = from; this.to = to; expectedThread = thread;
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}
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@Override
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public Long compute() {
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check(Thread.currentThread() == expectedThread,
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"Expected " + expectedThread + ", got " + Thread.currentThread());
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long range = to - from;
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if (range < THRESHOLD) {
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long acc = 0;
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for (long i = from; i <= to; i++)
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acc = acc + i;
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return acc;
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} else {
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long half = from + range / 2;
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SumTask t1 = new SumTask(from, half ,expectedThread);
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SumTask t2 = new SumTask(half+1, to ,expectedThread);
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if (half % 2 == 0) {
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t1.fork();
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return t2.compute() + t1.join();
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} else {
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invokeAll(t1, t2);
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try { return t1.get() + t2.get(); }
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catch (Exception x) { unexpected(x); return 0L;}
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}
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}
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}
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}
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public static class NullForkJoinWorkerThreadFactory
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implements ForkJoinWorkerThreadFactory
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{
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@Override
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public ForkJoinWorkerThread newThread(ForkJoinPool pool) {
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return null;
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}
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}
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//--------------------- Infrastructure ---------------------------
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static volatile int passed = 0, failed = 0;
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static void pass() {passed++;}
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static void fail() {failed++; /*Thread.dumpStack();*/}
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static void fail(String msg) {System.out.println(msg); fail();}
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static void unexpected(Throwable t) {failed++; t.printStackTrace();}
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static void check(boolean cond, String msg) {if (cond) pass(); else fail(msg);}
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static void equal(Object x, Object y) {
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if (x == null ? y == null : x.equals(y)) pass();
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else fail(x + " not equal to " + y);}
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public static void main(String[] args) throws Throwable {
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try {realMain(args);} catch (Throwable t) {unexpected(t);}
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System.out.printf("%nPassed = %d, failed = %d%n%n", passed, failed);
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if (failed > 0) throw new AssertionError("Some tests failed");}
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}
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