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I wanted to test the performance of concurrent http request in Go against node.js:

package main

import (
  "fmt"
  "time"
  "strconv"
  "net/http"
)

var responseCounter = 0
var requestCounter = 0
var count=0
var ch = make(chan int)

func sendRequest(){
    go func() {
        requestCounter++
        url := "https://www.google.co.in/#q=search_" +strconv.Itoa(requestCounter)
        resp, err := http.Get(url)
        if err != nil {
            fmt.Printf("\nError",err)
        }
        defer resp.Body.Close()
        count++
        ch <- count
        sendRequest()
    }()
}

func main() {

    for i := 1; i<100; i++{
        sendRequest()
    }

    for {
        select {
            case r := <-ch:
                fmt.Printf("\nChannel ",r)
            case <-time.After(50 * time.Millisecond):
                //sendRequest()
        }
    }
}

When I run this code the CPU usage goes very high (around 90%). Is there something wrong with this code? Have I used the Goroutines correctly?

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  • \$\begingroup\$ but you start infinitely many goroutines in your sendRequest, no? \$\endgroup\$ – akonsu Jan 9 '15 at 16:29
  • \$\begingroup\$ I did so because I wanted the requests to be continuous. So when one http request is complete I made another request by calling sendRequest(). Is there a better way to achieve this? \$\endgroup\$ – Sarita Jan 10 '15 at 15:52
  • \$\begingroup\$ try to wait for the goroutine to finish and then start another one. I do not know what is going on... \$\endgroup\$ – akonsu Jan 10 '15 at 16:19
  • \$\begingroup\$ So many data races!! (go {build,install,run,test} -race is your friend). \$\endgroup\$ – Dave C Apr 12 '15 at 17:00
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Inside SendRequst you are calling SendRequest again, which will make your stack full of recursive calls.

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