Thread.onSpinWait()方法在Java 9中引入。它是Thread类的一个静态方法，可以选择性地在忙等待循环中调用。它允许JVM在某些系统架构上发出处理器指令，以改善这种自旋等待循环的响应时间，并减少核心线程的功耗。它可以改善java程序的整体功耗，并允许其他核心线程以相同的功耗范围内更快地执行。
Syntax
<strong>public static void onSpinWait()</strong>
Example
的中文翻译为：示例
public class ThreadOnSpinWaitTest {
public static void main(final String args[]) throws InterruptedException {
final NormalTask task1 = new NormalTask();
final SpinWaitTask task2 = new SpinWaitTask();
final Thread thread1 = new Thread(task1);
thread1.start();
final Thread thread2 = new Thread(task2);
thread2.start();
new Thread(() -> {
try {
Thread.sleep(1000);
} catch(final InterruptedException e) {
e.printStackTrace();
} finally {
task1.start();
task2.sta*rt();
}
}).start();
thread1.join();
thread2.join();
}
private <strong>abstract </strong>static class Task implements Runnable {
volatile boolean canStart;
void start() {
this.canStart = true;
}
}
private <strong>static </strong>class NormalTask extends Task {
<strong>@Override</strong>
public void run() {
while(!this.canStart) {
}
System.out.println("Done!");
}
}
private <strong>static </strong>class SpinWaitTask extends Task {
<strong>@Override</strong>
public void run() {
while(!this.canStart) {
Thread.<strong>onSpinWait()</strong>;
}
System.out.println("Done!");
}
}
}输出
<strong>Done! Done!</strong>
