| Message ID | 1361973947-6136-1-git-send-email-stefanha@redhat.com |
|---|---|
| State | New |
| Headers | show |
Le Wednesday 27 Feb 2013 à 15:05:47 (+0100), Stefan Hajnoczi a écrit : > 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> > --- > net/socket.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/net/socket.c b/net/socket.c > index 396dc8c..c0dcc31 100644 > --- a/net/socket.c > +++ b/net/socket.c > @@ -439,6 +439,9 @@ 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 { > -- > 1.8.1.2 > > Reviewed-by: Benoit Canet <benoit@irqsave.net>
On Wed, Feb 27, 2013 at 03:05:47PM +0100, Stefan Hajnoczi wrote: > 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> ACK. Signed-off-by: Daniel P. Berrange <berrange@redhat.com> > --- > net/socket.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/net/socket.c b/net/socket.c > index 396dc8c..c0dcc31 100644 > --- a/net/socket.c > +++ b/net/socket.c > @@ -439,6 +439,9 @@ 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 { > -- Daniel
On Wed, Feb 27, 2013 at 04:49:16PM +0000, Daniel P. Berrange wrote: > On Wed, Feb 27, 2013 at 03:05:47PM +0100, Stefan Hajnoczi wrote: > > 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> > > ACK. > > Signed-off-by: Daniel P. Berrange <berrange@redhat.com> Hi Dan, QEMU usually only uses Singed-off-by: for authors and subsystem maintainers who merge the patch. Is it okay if I add a Reviewed-by: Daniel P. Berrange <berrange@redhat.com> instead? Stefan
On Thu, Feb 28, 2013 at 02:49:51PM +0100, Stefan Hajnoczi wrote: > On Wed, Feb 27, 2013 at 04:49:16PM +0000, Daniel P. Berrange wrote: > > On Wed, Feb 27, 2013 at 03:05:47PM +0100, Stefan Hajnoczi wrote: > > > 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> > > > > ACK. > > > > Signed-off-by: Daniel P. Berrange <berrange@redhat.com> > > Hi Dan, > QEMU usually only uses Singed-off-by: for authors and subsystem > maintainers who merge the patch. Ah, ok. > > Is it okay if I add a Reviewed-by: Daniel P. Berrange > <berrange@redhat.com> instead? Of course. Daniel
On Thu, Feb 28, 2013 at 01:55:58PM +0000, Daniel P. Berrange wrote: > On Thu, Feb 28, 2013 at 02:49:51PM +0100, Stefan Hajnoczi wrote: > > On Wed, Feb 27, 2013 at 04:49:16PM +0000, Daniel P. Berrange wrote: > > > On Wed, Feb 27, 2013 at 03:05:47PM +0100, Stefan Hajnoczi wrote: > > > > 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> > > > > > > ACK. > > > > > > Signed-off-by: Daniel P. Berrange <berrange@redhat.com> > > > > Hi Dan, > > QEMU usually only uses Singed-off-by: for authors and subsystem > > maintainers who merge the patch. > > Ah, ok. > > > > > Is it okay if I add a Reviewed-by: Daniel P. Berrange > > <berrange@redhat.com> instead? > > Of course. Thanks, done. Stefan
diff --git a/net/socket.c b/net/socket.c index 396dc8c..c0dcc31 100644 --- a/net/socket.c +++ b/net/socket.c @@ -439,6 +439,9 @@ 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 {
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> --- net/socket.c | 3 +++ 1 file changed, 3 insertions(+)