java - 我如何测量有多少线程正在执行一段代码？

Question

我正在尝试测量有多少线程同时执行一段代码。目前我正在(ab)为此使用信号量，有没有更好的方法？

final int MAX_THREADS = Integer.MAX_VALUE;

Semaphore s = new Semaphore(MAX_THREADS);

s.acquire(); // start of section

// do some computations

// track how many threads are running the section
trackThreads( (MAX_THREADS - s.availablePermits()) );         

s.release(); // end of section

Answer 1

使用 AtomicInteger而不是 Semaphore。

类似的东西:

AtomicInteger count = new AtomicInteger();

count.getAndIncrement();

// do some computations

// track how many threads are running the section
trackThreads( count.get() );         

count.getAndDecrement(); // end of section