Hi,
I have some doubts related to the HTTP client.
I have an HTTP service that in the handler calls synchronously to another
HTTP service (serviceA). (I will call it case 1).
func withoutGoroutine(w http.ResponseWriter, r *http.Request) {
httpGetA()
_, err := w.Write([]byte(``))
if err != nil {
log.Printf("%v", err)
}
}
The same service has another handler, it does the same that case 1 with an
additional asynchronous HTTP call to a different service (serviceB) using a
different HTTP client (I will call it case 2).
func withGoroutine(w http.ResponseWriter, r *http.Request) {
httpGetA()
_, err := w.Write([]byte(``))
if err != nil {
log.Printf("%v", err)
}
go httpGetB()
}
I run some load tests over these handlers with these results
Case 1
ab -n 500000 -c 50 0.0.0.0:8080/withoutgoroutine
...
Percentage of the requests served within a certain time (ms)
50% 3
66% 4
75% 4
80% 4
90% 5
95% 7
98% 10
99% 11
100% 38 (longest request)
Case 2
ab -n 500000 -c 50 0.0.0.0:8080/withgoroutine
...
Percentage of the requests served within a certain time (ms)
50% 5
66% 5
75% 6
80% 6
90% 8
95% 10
98% 14
99% 16
100% 42 (longest request)
Why case 2 has slower responses?
If in case 2 I add more asynchronous calls (two or three) the response time
were worst and worst.
I would expect the same response time.
To be sure about the problem is not the creation of goroutines, I created a
third case: Case 1 with the creation of goroutines but without an HTTP call.
func withSleepyGoroutine(w http.ResponseWriter, r *http.Request) {
httpGetA()
_, err := w.Write([]byte(``))
if err != nil {
log.Printf("%v", err)
}
go func() {
time.Sleep(1 * time.Millisecond)
}()
}
In cases 2 and 3, the goroutines are created after the HTTP response is
sent.
I made the load tests in different machines to dismiss a network issue.
The full source code is available in this Github repo.
https://github.com/juanpabloaj/go_http_with_concurrency
Thanks a lot for your help.
Regards
--
You received this message because you are subscribed to the Google Groups
"golang-nuts" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to golang-nuts+unsubscr...@googlegroups.com.
To view this discussion on the web visit
https://groups.google.com/d/msgid/golang-nuts/fce6ddc1-556b-4cde-9071-5fb129adb34dn%40googlegroups.com.
