Semaphore queues are FIFO ordered by default, an option exist to make them priority ordered but this can impact I/O performance because semaphores are used in I/O queues.

• 信号量队列默认是以FIFO的顺序排序的，可以通过已有的选项来使其以优先级排序，不过由于信号量会在I/O队列中使用，这样会影响I/O表现。