[ovs-discuss] Performance of openvswitch versus linux bridging with XEN

[nicholas.weaver at emc.com]

I have gotten Case 4 to work with KVM & Ubuntu with native bridging.

What distro are you using?

.nick
-
Nicholas Weaver
Mobile: 817.914.6166 | Email: nicholas.weaver at emc.com<mailto:nicholas.weaver at emc.com>
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From: Vijay Chander <vijay.chander at gmail.com<mailto:vijay.chander at gmail.com>>
Date: Thu, 19 Jan 2012 21:31:24 -0500
To: "discuss at openvswitch.org<mailto:discuss at openvswitch.org>" <discuss at openvswitch.org<mailto:discuss at openvswitch.org>>
Subject: [ovs-discuss] Performance of openvswitch versus linux bridging with XEN

We are having performance issues with XEN as opposed to VMWARE.

Pls take a look at the following cases (OVS - open vswitch, Bridge - native linux bridging)

Case 1  (no VM guest tagging):    VM1   VNIC1 ---- (no tag) ---  OVS ---(vlan X) --- PNIC1    ------(vlan X)---------       PNIC2 ---- (vlan X) ---- OVS --- (no tag) --- VNIC2 ---- VM2
Case 2  (no VM guest tagging):    VM1   VNIC1 ---- (no tag) ---  Bridge ------ PNIC1      ------(vlan X)---------       PNIC2 ---- (vlan X) ---- Bridge --- (no tag) --- VNIC2 ---- VM2
Case 3 (VM guest tagging):         VM1   VNIC1 ---- (vlan X) ---  OVS ---(vlan X) --- PNIC1    ------(vlan X)---------       PNIC2 ---- (vlan X) ---- OVS --- (vlan X) --- VNIC2 ---- VM2
Case 4 (VM guest tagging):         VM1   VNIC1 ---- (vlan X) ---  Bridge ---(vlan X) --- PNIC1    ------(vlan X)---------       PNIC2 ---- (vlan X) ---- Bridge --- (vlan X) --- VNIC2 ---- VM2

Case 4 does not work. So we moved to using OVS (open vswitch) because Case 3 works.

But performance for Case 2 is much better than performance for Case 1. This is making us think
about using bridging instead of open vswitch.  Any reason why this is the case ?

Has anyone done some benchmarking with xen+bridging and xen+open vswitch ? Pls
point me to the results if they are available online.

Also can someone pls point me to the data path architecture info for the open vswitch ?

I understand that open vswitch can be deployed in user mode or kernel mode. We are
mainly interested in kernel mode deployment for perf reasons.

We are even considering building the whole thing pulling in the fixes ourselves as opposed to using
the stuff that comes with xencenter 6.0 from citrix.

Any pointers will be great.

Thanks,
-vijay