Golang in the runtime. Understanding of Gosched ()

This is a creation in Article, where the information may have evolved or changed.

Runtime. Gosched () is used to yield CPU time slices. It's like running a relay race, a ran for a while to meet the Code runtime.gosched () the baton to B, a rest, b continue to run.

Look at the code:

Package main Import ("FMT""Runtime") Func say (Sstring) { forI: =0; I <2; i++{runtime. Gosched () fmt. Println (s)}} Func main () {go Say (" World") Say ("Hello")}

Output Result:

Hello

World

Hello

Note the results:

1, the first output of Hello, after the output of the world.

2, hello output 2, World output 1 (because the 2nd Hello output, the main thread exited, the 2nd world did not have a chance)

Put the runtime in the code. Gosched () is commented out and the result is:

Hello

Hello

Because say ("hello") This sentence takes up time, when it executes, the thread ends, and say ("World") has no chance.

As you can see here, the goroutins in Go is not running at the same time. In fact, if you do not pass in the code

Runtime. Gomaxprocs (n) where n is an integer,

Specifies the use of multicore, Goroutins are in a line thread, between them through the continuous letting out the time slices in turn to run, to achieve similar simultaneous effect.

Also need to learn a sentence:

When a goroutine is blocked, go automatically transfers other goroutines that are in the same system thread as the Goroutine to another system thread so that these goroutines do not block