Go client program generates a lot a sockets in TIME_WAIT state
The default http.Transport is opening and closing connections too quickly. Since all connections are to the same host:port combination, you need to increase MaxIdleConnsPerHost
to match your value for num_coroutines
. Otherwise, the transport will frequently close the extra connections, only to have them reopened immediately.
You can set this globally on the default transport:
http.DefaultTransport.(*http.Transport).MaxIdleConnsPerHost = numCoroutines
Or when creating your own transport
t := &http.Transport{
Proxy: http.ProxyFromEnvironment,
DialContext: (&net.Dialer{
Timeout: 30 * time.Second,
KeepAlive: 30 * time.Second,
}).DialContext,
MaxIdleConnsPerHost: numCoroutines,
MaxIdleConns: 100,
IdleConnTimeout: 90 * time.Second,
TLSHandshakeTimeout: 10 * time.Second,
ExpectContinueTimeout: 1 * time.Second,
}
Similar question: Go http.Get, concurrency, and "Connection reset by peer"