From af90becf4b91be3b45d9bbafa6366ed901c2572c Mon Sep 17 00:00:00 2001
From: Daniel Stenberg <daniel@haxx.se>
Date: Sun, 27 Sep 2015 23:20:13 +0200
Subject: [PATCH] http2: set TCP_NODELAY unconditionally

For a single-stream download from localhost, we managed to increase
transfer speed from 1.6MB/sec to around 400MB/sec, mostly because of
this single fix.
---
 lib/connect.c | 7 +++----
 lib/connect.h | 4 +++-
 lib/http2.c   | 5 +++++
 3 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/lib/connect.c b/lib/connect.c
index 8a74b73e5..ece6cf3f6 100644
--- a/lib/connect.c
+++ b/lib/connect.c
@@ -857,12 +857,11 @@ CURLcode Curl_is_connected(struct connectdata *conn,
   return result;
 }
 
-static void tcpnodelay(struct connectdata *conn,
-                       curl_socket_t sockfd)
+void Curl_tcpnodelay(struct connectdata *conn, curl_socket_t sockfd)
 {
 #ifdef TCP_NODELAY
   struct SessionHandle *data= conn->data;
-  curl_socklen_t onoff = (curl_socklen_t) data->set.tcp_nodelay;
+  curl_socklen_t onoff = (curl_socklen_t) 1;
   int level = IPPROTO_TCP;
 
 #if 0
@@ -1033,7 +1032,7 @@ static CURLcode singleipconnect(struct connectdata *conn,
   is_tcp = (addr.family == AF_INET) && addr.socktype == SOCK_STREAM;
 #endif
   if(is_tcp && data->set.tcp_nodelay)
-    tcpnodelay(conn, sockfd);
+    Curl_tcpnodelay(conn, sockfd);
 
   nosigpipe(conn, sockfd);
 
diff --git a/lib/connect.h b/lib/connect.h
index 91646c75e..c64328151 100644
--- a/lib/connect.h
+++ b/lib/connect.h
@@ -7,7 +7,7 @@
  *                            | (__| |_| |  _ <| |___
  *                             \___|\___/|_| \_\_____|
  *
- * Copyright (C) 1998 - 2014, Daniel Stenberg, <daniel@haxx.se>, et al.
+ * Copyright (C) 1998 - 2015, 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
@@ -102,6 +102,8 @@ CURLcode Curl_socket(struct connectdata *conn,
                      struct Curl_sockaddr_ex *addr,
                      curl_socket_t *sockfd);
 
+void Curl_tcpnodelay(struct connectdata *conn, curl_socket_t sockfd);
+
 #ifdef CURLDEBUG
 /*
  * Curl_connclose() sets the bit.close bit to TRUE with an explanation.
diff --git a/lib/http2.c b/lib/http2.c
index 05b919625..de6d03d39 100644
--- a/lib/http2.c
+++ b/lib/http2.c
@@ -34,6 +34,7 @@
 #include "multiif.h"
 #include "conncache.h"
 #include "url.h"
+#include "connect.h"
 
 /* The last #include files should be: */
 #include "curl_memory.h"
@@ -1441,6 +1442,10 @@ 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;
 }