在 Go 中,我可以使用 time.After
使休眠函数超时,但我不能对忙等待(或工作)的函数执行相同的操作。以下代码在一秒后返回 timed out
,然后挂起。
package main
import (
"fmt"
"time"
)
func main() {
sleepChan := make(chan int)
go sleep(sleepChan)
select {
case sleepResult := <-sleepChan:
fmt.Println(sleepResult)
case <-time.After(time.Second):
fmt.Println("timed out")
}
busyChan := make(chan int)
go busyWait(busyChan)
select {
case busyResult := <-busyChan:
fmt.Println(busyResult)
case <-time.After(time.Second):
fmt.Println("timed out")
}
}
func sleep(c chan<- int) {
time.Sleep(10 * time.Second)
c <- 0
}
func busyWait(c chan<- int) {
for {
}
c <- 0
}
为什么在第二种情况下不触发超时,我需要使用什么替代方法来中断工作中的 goroutines?
最佳答案
for {}
语句是一个独占单个处理器的无限循环。设置runtime.GOMAXPROCS
到 2 或更多以允许计时器运行。
例如,
package main
import (
"fmt"
"runtime"
"time"
)
func main() {
fmt.Println(runtime.GOMAXPROCS(0))
runtime.GOMAXPROCS(runtime.NumCPU())
fmt.Println(runtime.GOMAXPROCS(0))
sleepChan := make(chan int)
go sleep(sleepChan)
select {
case sleepResult := <-sleepChan:
fmt.Println(sleepResult)
case <-time.After(time.Second):
fmt.Println("timed out")
}
busyChan := make(chan int)
go busyWait(busyChan)
select {
case busyResult := <-busyChan:
fmt.Println(busyResult)
case <-time.After(time.Second):
fmt.Println("timed out")
}
}
func sleep(c chan<- int) {
time.Sleep(10 * time.Second)
c <- 0
}
func busyWait(c chan<- int) {
for {
}
c <- 0
}
输出(4 CPU 处理器):
1
4
timed out
timed out
关于concurrency - Go 超时 sleep 但不忙等待,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/22265245/