Gpars.withPool 线程在多次迭代后最终停止执行

Question

正在尝试使用 Gpars 执行并发操作。

Gpars.withPool(6) {
  someList.eachParallel {
    println "${Thread.currentThread}"
  }
}

最初它似乎有效

Thread[ForkJoinPool-1-worker-1,5,main] 
Thread[ForkJoinPool-1-worker-6,5,main] 
Thread[ForkJoinPool-1-worker-2,5,main]  
Thread[ForkJoinPool-1-worker-5,5,main] 
Thread[ForkJoinPool-1-worker-3,5,main]
Thread[ForkJoinPool-1-worker-4,5,main] 
Thread[ForkJoinPool-1-worker-1,5,main]
Thread[ForkJoinPool-1-worker-6,5,main]
Thread[ForkJoinPool-1-worker-2,5,main]

但是迭代一段时间后，一些线程停止执行。

Thread[ForkJoinPool-1-worker-2,5,main]
Thread[ForkJoinPool-1-worker-3,5,main]
Thread[ForkJoinPool-1-worker-2,5,main]
Thread[ForkJoinPool-1-worker-3,5,main] 
Thread[ForkJoinPool-1-worker-2,5,main] 
Thread[ForkJoinPool-1-worker-3,5,main]
Thread[ForkJoinPool-1-worker-2,5,main]

直到最后我们只剩下一个。

Thread[ForkJoinPool-1-worker-2,5,main]
Thread[ForkJoinPool-1-worker-2,5,main]
Thread[ForkJoinPool-1-worker-2,5,main]
Thread[ForkJoinPool-1-worker-2,5,main]
Thread[ForkJoinPool-1-worker-2,5,main]
Thread[ForkJoinPool-1-worker-2,5,main]

知道为什么会这样吗？保持所有线程活动的任何解决方案？

就我而言，可能值得一提的是我们的迭代速度约为 50k-200k。

Answer 1

以防其他人遇到同样的问题。他们的文档说：

Because GParsPool uses a Fork/Join pool (with work stealing), threads may not be applied to a waiting processing task even though they may appear idle. With a work-stealing algorithm, worker threads that run out of things to do can steal tasks from other threads that are still busy.

if you use GParsExecutorsPool , which doesn't use Fork/Join, you get the thread allocation behavior that you would naively expect.

基于此，我选择改用 GParsExecutorsPool。有了这个，所有线程都一致地执行，直到整个 eachParallel 进程结束。

GParsExecutorsPool.withPool(6) {
  someList.eachParallel {
    println "${Thread.currentThread}"
  }
}

Gpars.withPool 线程在多次迭代后最终停止执行

Gpars.withPool threads eventually stops executing after iterating numerous times

groovy

gpars