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. fbl > > > > I’m trying to quickly determine if we have a config issue, an > > Openstack issue or whether we’re hitting some sort of OVS limit as > > described. It seems to me that 1500 ports isn’t that many, but I’m not > > sure what sort of performance degradation I should be expecting above > > 1024 ports. The gateway node is so lightly loaded that I’d prefer to > > be able to handle a lot more networks on it before deploying another > > one. > > Are you adding ports one at a time with ovs-vsctl? If you can add them > in a batch, it will perform better. I guess we could also add a "daemon > mode" like ovn-nbctl, which would help a good deal too. > _______________________________________________ > discuss mailing list > disc...@openvswitch.org > https://mail.openvswitch.org/mailman/listinfo/ovs-discuss _______________________________________________ discuss mailing list disc...@openvswitch.org https://mail.openvswitch.org/mailman/listinfo/ovs-discuss