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

diff --git a/docs/libcurl/opts/CURLOPT_TCP_NODELAY.3 b/docs/libcurl/opts/CURLOPT_TCP_NODELAY.3
index efb258693d757afbc854de1e61d1b7bafd1ea429..bd19fbaf0df437788f7d7cf7f9af4fb4b2b1b21b 100644 (file)
--- a/docs/libcurl/opts/CURLOPT_TCP_NODELAY.3
+++ b/docs/libcurl/opts/CURLOPT_TCP_NODELAY.3
@@ -5,7 +5,7 @@
 .\" *                            | (__| |_| |  _ <| |___
 .\" *                             \___|\___/|_| \_\_____|
 .\" *
-.\" * Copyright (C) 1998 - 2014, Daniel Stenberg, <daniel@haxx.se>, et al.
+.\" * Copyright (C) 1998 - 2016, Daniel Stenberg, <daniel@haxx.se>, et al.
 .\" *
 .\" * This software is licensed as described in the file COPYING, which
 .\" * you should have received as part of this distribution. The terms
@@ -20,7 +20,7 @@
 .\" *
 .\" **************************************************************************
 .\"
-.TH CURLOPT_TCP_NODELAY 3 "19 Jun 2014" "libcurl 7.37.0" "curl_easy_setopt options"
+.TH CURLOPT_TCP_NODELAY 3 "30 Jun 2016" "libcurl 7.50.0" "curl_easy_setopt options"
 .SH NAME
 CURLOPT_TCP_NODELAY \- set the TCP_NODELAY option
 .SH SYNOPSIS
@@ -29,8 +29,8 @@ CURLOPT_TCP_NODELAY \- set the TCP_NODELAY option
 CURLcode curl_easy_setopt(CURL *handle, CURLOPT_TCP_NODELAY, long nodelay);
 .SH DESCRIPTION
 Pass a long specifying whether the TCP_NODELAY option is to be set or cleared
-(1 = set, 0 = clear). The option is cleared by default. This will have no
-effect after the connection has been established.
+(1 = set, 0 = clear). The option is set by default. This will have no effect
+after the connection has been established.
 
 Setting this option will disable TCP's Nagle algorithm. The purpose of this
 algorithm is to try to minimize the number of small packets on the network
@@ -43,13 +43,13 @@ need to be sent without delay. This is less efficient than sending larger
 amounts of data at a time, and can contribute to congestion on the network if
 overdone.
 .SH DEFAULT
-0
+1
 .SH PROTOCOLS
 All
 .SH EXAMPLE
 TODO
 .SH AVAILABILITY
-Always
+Always. The default was changed to 1 from 0 in 7.50.2.
 .SH RETURN VALUE
 Returns CURLE_OK
 .SH "SEE ALSO"

diff --git a/lib/http2.c b/lib/http2.c
index 8e10c6601ccba5232e5cedb5bf28ce32f961d66a..5bed6fcdf10de068035336f5a6dcc5e3e5cfbaf2 100644 (file)
--- 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 da48da6b9ff41ca1c34c16f39b45f037515416ed..bda3ccddbb155385ec02a52c5eeced9846b9459c 100644 (file)
--- 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;

diff --git a/src/tool_cfgable.c b/src/tool_cfgable.c
index 8b60a91b7041f22c21628566671885fec4cf9adf..567123b8222baef58d427d7f7687ca399a830fff 100644 (file)
--- a/src/tool_cfgable.c
+++ b/src/tool_cfgable.c
@@ -5,7 +5,7 @@
  *                            | (__| |_| |  _ <| |___
  *                             \___|\___/|_| \_\_____|
  *
- * Copyright (C) 1998 - 2015, Daniel Stenberg, <daniel@haxx.se>, et al.
+ * Copyright (C) 1998 - 2016, Daniel Stenberg, <daniel@haxx.se>, et al.
  *
  * This software is licensed as described in the file COPYING, which
  * you should have received as part of this distribution. The terms
@@ -41,6 +41,7 @@ void config_init(struct OperationConfig* config)
                           CURLPROTO_SMBS);
   config->proto_redir_present = FALSE;
   config->proto_default = NULL;
+  config->tcp_nodelay = TRUE; /* enabled by default */
 }
 
 static void free_config_fields(struct OperationConfig *config)

diff --git a/src/tool_operate.c b/src/tool_operate.c
index 2b53c9a857f72ae57840422f97a3b0fe9b2fd59a..97bb87b3d6c7f69ef1b052cfdb378283824d7ed4 100644 (file)
--- a/src/tool_operate.c
+++ b/src/tool_operate.c
@@ -792,8 +792,8 @@ static CURLcode operate_do(struct GlobalConfig *global,
           set_binmode(stdout);
         }
 
-        if(config->tcp_nodelay)
-          my_setopt(curl, CURLOPT_TCP_NODELAY, 1L);
+        if(!config->tcp_nodelay)
+          my_setopt(curl, CURLOPT_TCP_NODELAY, 0L);
 
         if(config->tcp_fastopen)
           my_setopt(curl, CURLOPT_TCP_FASTOPEN, 1L);

diff --git a/src/tool_setopt.c b/src/tool_setopt.c
index 690ce14a61bb20d68323149aef7b36a74cf9aabe..c854225e49fc80ab92352937062d624cdbd42226 100644 (file)
--- a/src/tool_setopt.c
+++ b/src/tool_setopt.c
@@ -5,7 +5,7 @@
  *                            | (__| |_| |  _ <| |___
  *                             \___|\___/|_| \_\_____|
  *
- * Copyright (C) 1998 - 2015, Daniel Stenberg, <daniel@haxx.se>, et al.
+ * Copyright (C) 1998 - 2016, Daniel Stenberg, <daniel@haxx.se>, et al.
  *
  * This software is licensed as described in the file COPYING, which
  * you should have received as part of this distribution. The terms
@@ -157,6 +157,7 @@ static const NameValue setopt_nv_CURLNONZERODEFAULTS[] = {
   NV1(CURLOPT_SSL_VERIFYHOST, 1),
   NV1(CURLOPT_SSL_ENABLE_NPN, 1),
   NV1(CURLOPT_SSL_ENABLE_ALPN, 1),
+  NV1(CURLOPT_TCP_NODELAY, 1),
   NVEND
 };