package main
import ()
func main() {
msgQueue := make(chan int, 1000000)
netAddr := "127.0.0.1"
token := make(chan int, 10)
for i := 0; i < 10; i++ {
token <- i
}
go RecvReq(netAddr, msgQueue)
for {
select {
case req := <-msgQueue:
go HandleReq(req, token)
}
}
}
func RecvReq(addr string,msgQueue chan int){
msgQueue<-//get from network
}
func HandleReq(msg int, token chan int) {
//step 1
t := <-token
//step 2
//codo here...(don't call runtime.park）
//step 3
//code here...(may call runtime.park)
//step 4
token <- t
}
System: 1cpu 2core
Go version:go1.3 linux/amd64
Problem description:
msgQueue revc request all the time by RecvReq,then the main goroutine create new goroutine all the time,but the waiting goroutine wait all the time.The first 10 goroutines stop at step 3,new goroutines followed stop at step 1.
Q1:How to make the waiting goroutine to run when new goroutine is being created all the time.
Q2:How to balance RevcReq and HandleReq? Revc msg rate is 10 times faster than Handle msg.
Alas this is not very clear from your question. But there are several issues here.
You create a buffered channel of size n then insert n items into it. Don't do this - or to be clearer, don't do this until you know it's needed. Buffered channels usually fall into the 'premature optimisation' category. Start with unbuffered channels so you can work out how the goroutines co-operate. When it's working (free of deadlocks), measure the performance, add buffering, try again.
Your select has only one guard. So it behaves just like the select wasn't there and the case body was the only code there.
You are trying to spawn off new goroutines for every message. Is this really what you wanted? You may find you can use a static mesh of goroutines, perhaps 10 in your case, and the result may be a program in which the intent is clearer. It would also give a small saving because the runtime would not have to spawn and clean up goroutines dynamically (however, you should be concerned with correct behaviour first, before worrying about any inefficiencies).
Your RecvReq is missing from the playground example, which is not executable.