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authorStefan Hajnoczi <stefanha@redhat.com>2013-02-27 15:05:47 +0100
committerStefan Hajnoczi <stefanha@redhat.com>2013-03-25 11:13:09 +0100
commit20048d0a12b1080f688ff9b82696134df1aa3607 (patch)
treec28b096d6126a8a1d6918d80f903338da4a4fa4d /net/socket.c
parentfe6344a05fba26e16863fefcb823242e579b0991 (diff)
downloadfocaccia-qemu-20048d0a12b1080f688ff9b82696134df1aa3607.tar.gz
focaccia-qemu-20048d0a12b1080f688ff9b82696134df1aa3607.zip
net: use socket_set_nodelay() for -netdev socket
Reduce -netdev socket latency by disabling the Nagle algorithm on
SOCK_STREAM sockets in net/socket.c.  Since we are tunelling Ethernet
over TCP we shouldn't artificially delay outgoing packets, let the guest
decide packet scheduling.

I already get sub-millisecond -netdev socket ping times on localhost, so
there was no measurable difference in my testing.  This won't hurt
though and may improve remote socket performance.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Benoit Canet <benoit@irqsave.net>
Reviewed-by: Daniel P. Berrange <berrange@redhat.com>
Diffstat (limited to 'net/socket.c')
-rw-r--r--net/socket.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/net/socket.c b/net/socket.c
index d8b35a23cb..b0c83e022c 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -438,6 +438,9 @@ static NetSocketState *net_socket_fd_init_stream(NetClientState *peer,
     s->fd = fd;
     s->listen_fd = -1;
 
+    /* Disable Nagle algorithm on TCP sockets to reduce latency */
+    socket_set_nodelay(fd);
+
     if (is_connected) {
         net_socket_connect(s);
     } else {