Send a bunch of HTTP requests via threads and goroutines

httpget.go

package main

import (
        "fmt"
        "http"
        "flag"
        "runtime"
        "bytes"
        "log"
)

var (
        threads = flag.Int("threads", 1, "number of threads")
        routines = flag.Int("goroutines", 1000, "number of goroutines")
        count = flag.Int("count", 10, "number of HTTP goroutines per goroutine")
        host = flag.String("host", "localhost:8080", "Hostname:port to connect to")
        method = flag.String("method", "POST", "HTTP method to use")
        path = flag.String("path", "/", "Path to request")
        payload = flag.String("payload", "", "Payload of the request")
        ctype = flag.String("content-type", "application/json", "Content-Type of payload")
)

func fetch(done chan<- bool) (okay bool) {
        defer func() {
                done <- okay
        }()

        url := &http.URL{
                Scheme: "http",
                Host: *host,
                Path: *path,
        }
        if len(url.Path) == 0 || url.Path[0] != '/' {
                url.Path = "/" + url.Path
        }

        body := bytes.NewBufferString(*payload)

        req, err := http.NewRequest(*method, url.String(), body)
        if err != nil {
                log.Printf("newrequest: %s", err)
                return false
        }

        if len(*payload) > 0 {
                req.Header.Set("Content-Type", *ctype)
        }

        resp, err := http.DefaultTransport.RoundTrip(req)
        if err != nil {
                log.Printf("roundtrip: %s", err)
                return false
        }

        if resp.StatusCode != 200 {
                log.Printf("response: %s", resp.Status)
                return false
        }

        return true
}

func main() {
        flag.Parse()

        runtime.GOMAXPROCS(*threads)

        done := make(chan bool)

        for i := 0; i < *routines; i++ {
                go func() {
                        for j := 0; j < *count; j++ {
                                fetch(done)
                        }
                }()
        }

        errors := 0
        for i := 0; i < *routines * *count; i++ {
                if !<-done {
                        errors++
                }
        }
        fmt.Printf("%d requests transmitted, %d errors; %.2f%% error rate\n",
                *routines * *count, errors, 100*float64(errors)/float64(*routines * *count))
}

Interesting. The current Go tip works for -goroutines=1 -count=5000
but it crashes for e.g. -goroutines=500 -count=1
At first glance, I have no idea why. Did you filled some issue about this?

unexpected fault address 0x3ea776a0
throw: fault
[signal 0xb code=0x1 addr=0x3ea776a0 pc=0x7fef3e9767aa]
runtime.throw+0x40 /go-tip/src/pkg/runtime/runtime.c:110
runtime.throw(0x632cba, 0x3ea776a0)
runtime.sigpanic+0xe7 /go-tip/src/pkg/runtime/linux/thread.c:314
runtime.sigpanic()
...