- Constantine Sapuntzakis filed bug report #2783090

  (http://curl.haxx.se/bug/view.cgi?id=2783090) pointing out that on windows
  we need to grow the SO_SNDBUF buffer somewhat to get really good upload
  speeds. http://support.microsoft.com/kb/823764 has the details. Friends
  confirmed that simply adding 32 to CURL_MAX_WRITE_SIZE is enough.

1 files changed, 23 insertions, 0 deletions

diff --git a/lib/connect.c b/lib/connect.c
index c1206cee5..7727bf017 100644
--- a/lib/connect.c
+++ b/lib/connect.c
@@ -704,6 +704,27 @@ static void nosigpipe(struct connectdata *conn,
 #define nosigpipe(x,y)
 #endif
 
+#ifdef WIN32
+/* When you run a program that uses the Windows Sockets API, you may
+   experience slow performance when you copy data to a TCP server.
+
+   http://support.microsoft.com/kb/823764
+
+   Work-around: Make the Socket Send Buffer Size Larger Than the Program Send
+   Buffer Size
+
+*/
+static void sndbufset(struct connectdata *conn,
+                      curl_socket_t sockfd)
+{
+  int val = CURL_MAX_WRITE_SIZE + 32;
+  setsockopt(sockfd, SOL_SOCKET, SO_SNDBUF, (const char *)&val, sizeof(val));
+}
+#else
+#define sndbufset(x,y)
+#endif
+
+
 /* singleipconnect() connects to the given IP only, and it may return without
    having connected if used from the multi interface. */
 static curl_socket_t
@@ -807,6 +828,8 @@ singleipconnect(struct connectdata *conn,
 
   nosigpipe(conn, sockfd);
 
+  sndbufset(conn, sockfd);
+
   if(data->set.fsockopt) {
     /* activate callback for setting socket options */
     error = data->set.fsockopt(data->set.sockopt_client,