Hey,Since we once again got hit by the TCP_NODELAY causing a weirdo performance behavior, I move to making it enabled by default. As the attached patch shows.
Mentioned here to allow you to protest, agree or discuss bikeshed colors. If no objections show up, I'll merge tomorrow. -- / daniel.haxx.se
From afb4ec57e66e2236ae4399325e8e633e358275ae Mon Sep 17 00:00:00 2001 From: Daniel Stenberg <[email protected]> Date: Thu, 30 Jun 2016 14:56:02 +0200 Subject: [PATCH] CURLOPT_TCP_NODELAY: now enabled by default MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit After a few wasted hours hunting down the reason for slowness during a TLS handshake that turned out to be because of TLS_NODELAY not being set, I think we have enough motivation to toggle the default for this option. We now enable TLS_NODELAY by default and allow applications to switch it off. Thanks-to: Tim Rühsen Bug: https://curl.haxx.se/mail/lib-2016-06/0143.html --- docs/libcurl/opts/CURLOPT_TCP_NODELAY.3 | 12 ++++++------ lib/http2.c | 4 ---- lib/url.c | 1 + 3 files changed, 7 insertions(+), 10 deletions(-) diff --git a/docs/libcurl/opts/CURLOPT_TCP_NODELAY.3 b/docs/libcurl/opts/CURLOPT_TCP_NODELAY.3 index efb2586..eed8394 100644 --- a/docs/libcurl/opts/CURLOPT_TCP_NODELAY.3 +++ b/docs/libcurl/opts/CURLOPT_TCP_NODELAY.3 @@ -3,11 +3,11 @@ .\" * Project ___| | | | _ \| | .\" * / __| | | | |_) | | .\" * | (__| |_| | _ <| |___ .\" * \___|\___/|_| \_\_____| .\" * -.\" * Copyright (C) 1998 - 2014, Daniel Stenberg, <[email protected]>, et al. +.\" * Copyright (C) 1998 - 2016, Daniel Stenberg, <[email protected]>, et al. .\" * .\" * This software is licensed as described in the file COPYING, which .\" * you should have received as part of this distribution. The terms .\" * are also available at https://curl.haxx.se/docs/copyright.html. .\" * @@ -18,21 +18,21 @@ .\" * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY .\" * KIND, either express or implied. .\" * .\" ************************************************************************** .\" -.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 #include <curl/curl.h> 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 (where "small packets" means TCP segments less than the Maximum Segment Size (MSS) for the network). @@ -41,16 +41,16 @@ Maximizing the amount of data sent per TCP segment is good because it amortizes the overhead of the send. However, in some cases small segments may 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 7.50.0. .SH RETURN VALUE Returns CURLE_OK .SH "SEE ALSO" .BR CURLOPT_SOCKOPTFUNCTION "(3), " CURLOPT_TCP_KEEPALIVE "(3), " diff --git a/lib/http2.c b/lib/http2.c index efc082d..393bf47 100644 --- a/lib/http2.c +++ b/lib/http2.c @@ -1848,14 +1848,10 @@ CURLcode Curl_http2_setup(struct connectdata *conn) conn->bundle->multiuse = BUNDLE_MULTIPLEX; 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; } CURLcode Curl_http2_switched(struct connectdata *conn, const char *mem, size_t nread) diff --git a/lib/url.c b/lib/url.c index 258a286..66e2af2 100644 --- a/lib/url.c +++ b/lib/url.c @@ -600,10 +600,11 @@ CURLcode Curl_init_userdefined(struct UserDefined *set) */ set->tcp_keepalive = FALSE; 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; set->expect_100_timeout = 1000L; /* Wait for a second by default. */ -- 2.8.1
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