Flush after writing pending TLS data.
authorSteinar H. Gunderson <sgunderson@bigfoot.com>
Tue, 10 Apr 2018 15:58:38 +0000 (17:58 +0200)
committerSteinar H. Gunderson <sgunderson@bigfoot.com>
Tue, 10 Apr 2018 15:58:38 +0000 (17:58 +0200)
Cuts something like 600 ms away from the initial TLS handshake,
as we kept having unflushed data that would require waiting for
the 200 ms TCP_CORK timer.

server.cpp

index 0e056fb..551679b 100644 (file)
@@ -748,6 +748,22 @@ sending_data_again:
        }
 }
 
+namespace {
+
+void flush_pending_data(int sock)
+{
+       // Flush pending data, which would otherwise wait for the 200ms TCP_CORK timer
+       // to elapsed; does not cancel out TCP_CORK (since that still takes priority),
+       // but does a one-off flush.
+       int one = 1;
+       if (setsockopt(sock, SOL_TCP, TCP_NODELAY, &one, sizeof(one)) == -1) {
+               log_perror("setsockopt(TCP_NODELAY)");
+               // Can still continue.
+       }
+}
+
+}  // namespace
+
 bool Server::send_pending_tls_data(Client *client)
 {
        // See if there's data from the TLS library to write.
@@ -780,9 +796,15 @@ send_data_again:
                return true;
        }
        if (ret > 0 && size_t(ret) == client->tls_data_left_to_send) {
-               // All data has been sent, so we don't need to go to sleep.
+               // All data has been sent, so we don't need to go to sleep
+               // (although we are likely to do so immediately afterwards,
+               // due to lack of client data).
                tls_buffer_clear(client->tls_context);
                client->tls_data_to_send = nullptr;
+
+               // Flush the data we just wrote, since the client probably
+               // is waiting for it.
+               flush_pending_data(client->sock);
                return false;
        }
 
@@ -1290,13 +1312,7 @@ bool Server::more_requests(Client *client)
        // Log to access_log.
        access_log->write(client->get_stats());
 
-       // Flush pending data; does not cancel out TCP_CORK (since that still takes priority),
-       // but does a one-off flush.
-       int one = 1;
-       if (setsockopt(client->sock, SOL_TCP, TCP_NODELAY, &one, sizeof(one)) == -1) {
-               log_perror("setsockopt(TCP_NODELAY)");
-               // Can still continue.
-       }
+       flush_pending_data(client->sock);
 
        // Switch states and reset the parsers. We don't reset statistics.
        client->state = Client::READING_REQUEST;