On Tue, Feb 26, 2013 at 05:31:04PM +0100, Stefan Hajnoczi wrote: > On Mon, Feb 25, 2013 at 07:02:30PM -0600, clow...@clownix.net wrote: > > The associated file contains a README that will guide you through the > > experiment that shows the difference between unix socket carried pings: > > 0.7ms and inet carried pings: 40ms!!! > > There is no fundamental reason for inet sockets to have a 40 millisecond > round-trip time on localhost. I remember from years ago that Solaris > "fuses" localhost inet sockets and bypasses TCP for them. > > Adding a call to socket_set_nodelay() net/socket.c might help.
Yes, I'm pretty sure it will be the nagle algorithm that is causing this delay. Localhost IP sockets can round-trip ICMP packets in <0.1 ms If we don't want to disable nagle by default here, we could at least make it a configurable option for people. Regards, Daniel -- |: http://berrange.com -o- http://www.flickr.com/photos/dberrange/ :| |: http://libvirt.org -o- http://virt-manager.org :| |: http://autobuild.org -o- http://search.cpan.org/~danberr/ :| |: http://entangle-photo.org -o- http://live.gnome.org/gtk-vnc :|
