[ovs-discuss] [ovs-dev] OVS performance with Kernel Datapath of Linux upstream vs Linux OVS tree.

[Jarno Rajahalme]

> On Apr 12, 2017, at 12:49 AM, Kapil Adhikesavalu <kapil20084 at gmail.com> wrote:
> 
> Hi,
> 
> Is there any performance difference with using the OVS kernel Datapath
> available part of Linux upstream Vs the module built from Linux OVS tree.
> 

OVS tree kernel module has an Exact Match Cache, which generally improves performance. Upstream linux openvswitch module does not have it.

> So far i have been using the DP part of the Linux upstream and as NAT
> feature requires Linux version 4.6, i plan to switch to DP module built
> from OVS tree.
> 
> 1. In general is there any performance between using these two ? or would
> it vary based on the features being in use.
> 2. I am currently using VXLAN and L2 forwarding + NAT(plan to use it),
> would like to know if there could be any performance difference expected
> when i switch from upstream DP to KLM.
> 
> I didn't any specific mention about performance in FAQ -
> http://docs.openvswitch.org/en/latest/faq/releases/ expect for this
> statement 'Certain features require kernel support to function or to have
> reasonable performance.’
> 

This note relates to using OVS with an older (upstream) kernel module. While we maintain backwards compatibility, newer features perform better with newer kernel module having explicit support for the feature.

  Jarno

> Regards
> Kapil.
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