concurrency - goroutines 是如何工作的？ (或 : goroutines and OS threads relation)

Question

其他 goroutine 如何在调用系统调用时继续执行？ (使用 GOMAXPROCS=1 时)
据我所知，在调用系统调用时，线程放弃控制权，直到系统调用返回。Go 如何在不为每个blocking-on-syscall goroutine 创建系统线程的情况下实现这种并发？

来自 documentation :

Goroutines

They're called goroutines because the existing terms—threads, coroutines, processes, and so on—convey inaccurate connotations. A goroutine has a simple model: it is a function executing concurrently with other goroutines in the same address space. It is lightweight, costing little more than the allocation of stack space. And the stacks start small, so they are cheap, and grow by allocating (and freeing) heap storage as required.

Goroutines are multiplexed onto multiple OS threads so if one should block, such as while waiting for I/O, others continue to run. Their design hides many of the complexities of thread creation and management.

Answer 1

如果一个 goroutine 正在阻塞，运行时将启动一个新的 OS 线程来处理其他 goroutine，直到阻塞的 goroutine 停止阻塞。

引用:https://groups.google.com/forum/#!topic/golang-nuts/2IdA34yR8gQ