Il 26/02/2013 17:51, Daniel P. Berrange ha scritto: > 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.
The guest will do Nagle's algorithm on its own, there's no reason to keep it on the host. Paolo
