CURLOPT_TCP_NODELAY: now enabled by default

After a few wasted hours hunting down the reason for slowness during a
TLS handshake that turned out to be because of TCP_NODELAY not being
set, I think we have enough motivation to toggle the default for this
option. We now enable TCP_NODELAY by default and allow applications to
switch it off.

This also makes --tcp-nodelay unnecessary, but --no-tcp-nodelay can be
used to disable it.

Thanks-to: Tim Rühsen
Bug: https://curl.haxx.se/mail/lib-2016-06/0143.html

2 files changed, 1 insertions, 4 deletions

diff --git a/lib/http2.c b/lib/http2.c
index 8e10c6601..5bed6fcdf 100644
--- a/lib/http2.c
+++ b/lib/http2.c
@@ -1849,10 +1849,6 @@ CURLcode Curl_http2_setup(struct connectdata *conn)
   infof(conn->data, "Connection state changed (HTTP/2 confirmed)\n");
   Curl_multi_connchanged(conn->data->multi);
 
-  /* switch on TCP_NODELAY as we need to send off packets without delay for
-     maximum throughput */
-  Curl_tcpnodelay(conn, conn->sock[FIRSTSOCKET]);
-
   return CURLE_OK;
 }
 
diff --git a/lib/url.c b/lib/url.c
index da48da6b9..bda3ccddb 100644
--- a/lib/url.c
+++ b/lib/url.c
@@ -602,6 +602,7 @@ CURLcode Curl_init_userdefined(struct UserDefined *set)
   set->tcp_keepintvl = 60;
   set->tcp_keepidle = 60;
   set->tcp_fastopen = FALSE;
+  set->tcp_nodelay = TRUE;
 
   set->ssl_enable_npn = TRUE;
   set->ssl_enable_alpn = TRUE;