I made some tests with OpenStack Havana release with ML2 plugin and OVS agent. Config on Compute node : # ovs-vsctl -V ovs-vsctl (Open vSwitch) 2.0.0 # uname -r 3.2.0-41-generic
I start two VM on the same compute node with an interface on a same network segmentation. By default, a veth pair is used between the Linux bridge (qbr) and the OVS bridge (br-int) for each VM interface. I set a simple netperf TCP test and I get a throughput of 2Gb/s. I replay this test after change the veth interfaces by an internal OVS port. The throughput increase to 13Gb/s. A patch [1] was already done to use internal instead of a veth. [1] https://review.openstack.org/#/c/46911/ Édouard. On Tue, Dec 10, 2013 at 10:15 PM, Justin Pettit <jpet...@nicira.com> wrote: > On Dec 10, 2013, at 12:17 PM, Wang, Baoyuan <baoyuan.w...@tekcomms.com> wrote: > >> Thank you for your response. I could not find much information about OVS >> patch port by google search. Most of them are talking about how to configure >> it. Do you have any information related to the design/implementation other >> than reading the code ? > > There's not a lot to describe on the implementation. Before 1.10, if you > created two bridges in OVS, two datapaths would be created in the kernel. > The patch port would create a port that you could send traffic to in one > datapath and it would pop into the other datapath for processing. The > implementation was very simple--it would just turn the send on one end into a > receive on the other. > > In 1.10, we went to a single datapath model where regardless of how many > bridges were created, they would share a single datapath in the kernel. With > this model, we were able to optimize patch ports by having ovs-vswitchd > figure out what would happen in both bridges, and then push down a single > flow into the datapath. > >> I do have some version of OVS code with me (v1.9.3). > > As I mentioned before, the patch port optimization was introduced in 1.10. > >> It seems to me that OVS still has to work on multiple flow tables with patch >> ports. It might save one loop comparing with veth pair, that is, patch port >> directly uses the peer to work on peer's flow table instead of going the >> main processing loop. Please correct me because I am not familiar with the >> detail OVS design/implementation. My code research has been spot check. For >> example, I only checked the files like vport-patch.c and vport.c. For >> Telecom industry, those extra processing on every compute nodes for every >> packet will add up quickly. > > The optimization saves an extra lookup in the kernel datapath and an extra > trip to userspace to figure out what happens in the second bridge. > > --Justin > > > _______________________________________________ > discuss mailing list > discuss@openvswitch.org > http://openvswitch.org/mailman/listinfo/discuss _______________________________________________ discuss mailing list discuss@openvswitch.org http://openvswitch.org/mailman/listinfo/discuss
