Patchwork [1/7] net: use socket_set_nodelay() for -netdev socket

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Submitter Stefan Hajnoczi
Date March 25, 2013, 12:26 p.m.
Message ID <1364214373-2444-2-git-send-email-stefanha@redhat.com>
Download mbox | patch
Permalink /patch/230699/
State New
Headers show

Comments

Stefan Hajnoczi - March 25, 2013, 12:26 p.m.
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>
---
 net/socket.c | 3 +++
 1 file changed, 3 insertions(+)

Patch

diff --git a/net/socket.c b/net/socket.c
index d8b35a2..b0c83e0 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 {