[ovs-discuss] TSO Support for OVS-DPDK

Ian Stokes ian.stokes at intel.com
Wed May 15 09:08:10 UTC 2019


On 5/15/2019 9:05 AM, Harsh Gondaliya wrote:
> Dear Team,
> 
> Since long I've been figuring out how to enable TSO support is OVS-DPDK 
> bridge.
> 
> I am trying to perform Inter-VM communication within same host (L2 
> forwarding). I get significantly less throughput in OVS-DPDK as compared 
> to OVS bridge for the same arrangement.
> 
> I have realised that OVS-DPDK bridge due to its lack of support for TSO 
> is not able to give high throughput results.
> 
> There has been some work done in this regard, but, I am not able to 
> understand what all config need to done or what patches need to be 
> applied in order to have TSO support in OVS-DPDK.
> 
> Being a beginner with these packages and Linux, may I please get a sort 
> of detailed description of what can be done to achieve TSO support in 
> OVS-DPDK?
> 

Hi,

TSO is not supported currently in OVS DPDK. TSO essentially requires the 
enablement of multi segment mbuf in OVS as well as TSO enablement.

There were patches proposed previously to enable both of these but they 
have not made it upstream to date due to concerns around their impact 
for non TSO usecases as well as some of the fundamental changes 
introduced WRT to the mbuf itself.

The series will be re-visited at some stage in the future once these 
issue can be addressed.

In the meantime if you wish to test the series that was available I 
would advise downloading the following patch series.

https://patchwork.ozlabs.org/project/openvswitch/list/?series=85802&state=*

https://patchwork.ozlabs.org/project/openvswitch/list/?series=85807&state=*

These will not apply to head of master any more so you will have to 
apply them on top of the following commit manually:

adb3f0b ("python: Avoid flake8 warning for unused variables.")

For tips on configuring MSEG/TSO there are instructions introduced in 
the cover letter and documentation of the patch series that can be 
consulted.

Multiseg enablement documentation (Setup steps etc.).
https://mail.openvswitch.org/pipermail/ovs-dev/2019-January/355111.htmll

TSO Documentation (Setup steps etc.)
https://mail.openvswitch.org/pipermail/ovs-dev/2019-January/355118.html

Cover letters (Performance figures, usecases, known issues).
https://mail.openvswitch.org/pipermail/ovs-dev/2019-January/355103.html
https://mail.openvswitch.org/pipermail/ovs-dev/2019-January/355115.html


HTL
Ian





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