From ad40ba4b68353b78a9bc822013f26dbc39e96261 Mon Sep 17 00:00:00 2001 From: Andreas Gustafsson Date: Wed, 7 Mar 2018 23:26:15 +0100 Subject: slirp: disable Nagle in outgoing connections MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit When setting up an outgoing user mode networking TCP connection, disable the Nagle algorithm in the host-side connection. Either the guest is already doing Nagle, in which case there is no point in doing it twice, or it has chosen to disable it, in which case we should respect that choice. This change speeds up GDB remote debugging over TCP over user mode networking (with GDB runing on the guest) by multiple orders of magnitude, and has been part of the local patches applied by pkgsrc since 2012 with no reported ill effects. Signed-off-by: Andreas Gustafsson Reviewed-by: Kamil Rytarowski Reviewed-by: Philippe Mathieu-Daudé Signed-off-by: Samuel Thibault --- tcp_subr.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/tcp_subr.c b/tcp_subr.c index d72597c..02e7f7c 100644 --- a/tcp_subr.c +++ b/tcp_subr.c @@ -414,6 +414,8 @@ int tcp_fconnect(struct socket *so, unsigned short af) socket_set_fast_reuse(s); opt = 1; qemu_setsockopt(s, SOL_SOCKET, SO_OOBINLINE, &opt, sizeof(opt)); + opt = 1; + qemu_setsockopt(s, IPPROTO_TCP, TCP_NODELAY, &opt, sizeof(opt)); addr = so->fhost.ss; DEBUG_CALL(" connect()ing") -- cgit v1.1