On Thu, May 02, 2019 at 04:44:42PM -0300, Flavio Leitner via discuss wrote: > On Tue, Apr 30, 2019 at 04:50:48PM -0700, Ben Pfaff wrote: > > On Fri, Apr 26, 2019 at 11:52:22AM -0500, William Konitzer wrote: > > > I'm reading > > > (http://www.openvswitch.org/support/dist-docs/ovs-vswitchd.8.txt > > > section LIMITS) and it says "Performance will degrade beyond 1,024 > > > ports per bridge due to fixed hash table sizing.” Do we have a little > > > more info on what that means and what to expect for less experienced > > > users like myself? > > > > I think that this comment is now obsolete. There was a fairly recent > > change that should have reduced the cost of a port. The kernel hash > > table is still fixed in size but I don't think it's accessed on any fast > > path so I think in practice it doesn't matter. > > > > > The background here is we’re working with OpenStack and seeing > > > performance issues when lots of networks are created.. Once we have > > > more than about 1500 ports on the br-int on a gateway node it seems to > > > take a long time to add new ports. > > You might want to bump the default netdev_max_backlog because that > is the maximum amount of packets queued. So, if you have too many > ports, there will be either packet loss, or slow path'ed traffic.
To clarify, it depends on the actions. If you are using action NORMAL and there is a broadcast for example, all ports need a packet copy, which means more than 1k packets will be queued. IIRC OvS will slow path this case to prevent packet loss in the recent versions. fbl _______________________________________________ discuss mailing list disc...@openvswitch.org https://mail.openvswitch.org/mailman/listinfo/ovs-discuss
