Java windows上的虚假唤醒。可能吗?
我最近学会了“虚假唤醒” 有人说这个问题只可能出现在某些类型的Linux PC上 我使用windows 我写了一个关于虚假唤醒的测试。我得到的结果是这是可能的。但我想给你看一下这个测试。也许我在什么地方出错了 我的初始变体:Java windows上的虚假唤醒。可能吗?,java,concurrency,notifications,synchronization,wait,Java,Concurrency,Notifications,Synchronization,Wait,我最近学会了“虚假唤醒” 有人说这个问题只可能出现在某些类型的Linux PC上 我使用windows 我写了一个关于虚假唤醒的测试。我得到的结果是这是可能的。但我想给你看一下这个测试。也许我在什么地方出错了 我的初始变体: import java.util.Random; import java.util.concurrent.*; import java.util.concurrent.atomic.AtomicInteger; public class TestSpuriousWakeu
import java.util.Random;
import java.util.concurrent.*;
import java.util.concurrent.atomic.AtomicInteger;
public class TestSpuriousWakeups {
static final int MAX_THREADS = 600;
static final Object mutex = new Object();
static final CountDownLatch allThreadsStarted =
new CountDownLatch(MAX_THREADS);
static final CountDownLatch allThreadsFinished =
new CountDownLatch(1);
static /*final*/ volatile AtomicInteger processedThreads = new AtomicInteger();
static /*final*/ volatile AtomicInteger notifiedThreads = new AtomicInteger();
final int n = 10;
static volatile boolean continueCondition = true;
static final Random sleepRandom = new Random();
static class Worker extends Thread {
public void run() {
try {
synchronized (mutex) {
allThreadsStarted.countDown();
mutex.wait();
}
continueCondition = true;
} catch (Exception e) {
throw new RuntimeException(e);
} finally {
processedThreads.incrementAndGet();
}
}
}
static class Notifier extends Thread {
public void run() {
while (true) {
if (processedThreads.get() == MAX_THREADS)
break;
synchronized (mutex) {
doStuff();
mutex.notify();
continueCondition = false;
notifiedThreads.incrementAndGet();
}
}
allThreadsFinished.countDown();
}
// just to emulate some activity
void doStuff() {
try { Thread.sleep(sleepRandom.nextInt(5)); }
catch (InterruptedException e) {
throw new RuntimeException(e);
}
}
}
public static void main(String[] args) throws Exception {
for (int i = 0; i < MAX_THREADS; i++)
new Worker().start();
// wait for all workers to start execution
allThreadsStarted.await();
new Notifier().start();
// wait for all workers and notifier to finish execution
allThreadsFinished.await();
System.out.println("Spurious wakeups count: "
+ (MAX_THREADS - notifiedThreads.get()));
}
}
所以不同的价值观对我来说很奇怪
我添加了一对要运行的行方法:
static class Notifier extends Thread {
public void run() {
while (true) {
while (!continueCondition) //added string
doStuff(); //added string
// all threads finished their execution
if (processedThreads.get() == MAX_THREADS)
break;
synchronized (mutex) {
doStuff();
mutex.notify();
continueCondition = false;
notifiedThreads.incrementAndGet();
}
}
allThreadsFinished.countDown();
}
在那之后,我再也找不到别的东西了
Spurious wakeups count: 0
在我的实验中,这真的是虚假的唤醒还是错误
附言
我注意到我看到了负数。因此,显然这是实验错误。但我不明白原因。两件事
Spurious wakeups count: 0