4.4、Golang 并发编程-runtime包
runtime定义了协程管理的包
Gosched
让出执行权限
示例
package main
import (
"fmt"
)
func show() {
for i := 0; i < 2; i++ {
fmt.Printf("show i: %v\n", i)
}
}
func main() {
go show()
for i := 0; i < 2; i++ {
fmt.Printf("main i: %v\n", i)
}
fmt.Println("end")
}
输出
main i: 0 main i: 1 end
示例 2
package main
import (
"fmt"
"runtime"
)
func show() {
for i := 0; i < 2; i++ {
fmt.Printf("show i: %v\n", i)
}
}
func main() {
go show()
for i := 0; i < 2; i++ {
// 让出执行权限，给其他子协程执行
runtime.Gosched()
fmt.Printf("main i: %v\n", i)
}
fmt.Println("end")
}
输出
show i: 0 main i: 0 main i: 1 end
Goexit
退出当前协程
示例
package main
import (
"fmt"
"runtime"
"time"
)
func show() {
for i := 0; i < 10; i++ {
fmt.Printf("show i: %v\n", i)
if i >= 5 {
runtime.Goexit()
}
}
}
func main() {
go show()
time.Sleep(time.Second)
fmt.Println("end")
}
输出
show i: 0 show i: 1 show i: 2 show i: 3 show i: 4 show i: 5 end
GOMAXPROCS
设置CPU数量
package main
import (
"fmt"
"runtime"
"time"
)
func show(name string) {
for i := 0; i < 10; i++ {
fmt.Printf("%v i: %v\n", name, i)
}
}
func main() {
// 查看CPU核数
fmt.Printf("runtime.NumCPU(): %v\n", runtime.NumCPU())
// runtime.NumCPU(): 8
// 设置CPU数量
runtime.GOMAXPROCS(2)
go show("A")
go show("B")
time.Sleep(time.Second)
fmt.Println("end")
}