控制EpollWait的msec优势在哪？

[M6ZeroG]

gev/poller/epoll.go

Lines 145 to 156 in 16e310c

	for {
	n, err := unix.EpollWait(ep.fd, events, msec)
	if err != nil && err != unix.EINTR {
	log.Error("EpollWait: ", err)
	continue
	}
	if n <= 0 {
	msec = -1
	runtime.Gosched()
	continue
	}
	msec = 0

阻塞的EpollWait调用在阻塞线程时应该也会主动让出CPU吧，看上去效果和上面runtime.Gosched() 的效果一样。还是说这里有什么神奇操作。