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authorAndreas Gustafsson <gson@gson.org>2018-03-07 23:26:15 +0100
committerSamuel Thibault <samuel.thibault@ens-lyon.org>2018-05-31 21:19:24 +0200
commit058665b9fe8b00c799b3db5d9202b007fab1c2fb (patch)
treebae041f69b7c4b8ebaeda80f7b20c989c2b06820
parentf18d137542a48150d177031fc6c54786179bf2a3 (diff)
slirp: disable Nagle in outgoing connections
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 <gson@gson.org> Reviewed-by: Kamil Rytarowski <n54@gmx.com> Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org> Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
-rw-r--r--slirp/tcp_subr.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/slirp/tcp_subr.c b/slirp/tcp_subr.c
index da0d53743f..8d0f94b75f 100644
--- a/slirp/tcp_subr.c
+++ b/slirp/tcp_subr.c
@@ -416,6 +416,8 @@ 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")