[dpdk-dev] [PATCH v5 00/29] Support VFD and DPDK PF + kernel VF on i40e

Vincent JARDIN vincent.jardin at 6wind.com
Tue Jan 10 14:29:55 CET 2017

Hi Scott,

Le 04/01/2017 à 22:09, Scott Daniels a écrit :
>  With holidays we are a bit late with our thoughts, but would like to
>  toss them into the mix.

Same, I hope I am not missing emails. I do appreciate your arguments, it 
provides lot of light. See below,

>  The original NAK is understandable, however having the ability to
>  configure the PF via DPDK is advantageous for several reasons:
>  1) While some functions may be duplicated and/or available from the kernel
>  driver, it is often not possible to introduce new kernel drivers into
>  production without a large amount of additional testing of the entire
>  platform which can cause a significant delay when introducing a DPDK based
>  product.  If the PF control is a part of the DPDK environment, then only
>  the application needs to pass the operational testing before deployment; a
>  much more simple task.

So we agree: you confirm that your foresee the benefits of using DPDK to 
*bypass the role of the Kernel being the PF* of reference for the 

>  2) If the driver changes are upstreamed into the kernel proper, the
>  difficulty of operational readiness testing increases as a new kernel is
>  introduced, and further undermines the ability to quickly and easily
>  release a DPDK based application into production.  While the application
>  may eventually fall back on driver and/or kernel support, this could be
>  years away.

I do agree with the benefits of the agilities and the upsides it brings. 
But they are other options to get the same agility without creating a 
fragmentation of PFs.

For example, you do not have to update the whole kernel, you can just 
update the PF kernel module that can be upgraded with the latest needed 

>  3) As DPDK is being used to configure the NIC, it just seems to make
>  sense, for consistency, that the configuration capabilities should include
>  the ability to configure the PF as is proposed.

 From this perspective, the kernel modules are fine for the PF: most 
kernels of hypervisors support it without the need to upgrade their kernels.

To summarize, I understand that you need a flexible way to upgrade PF 
features without touching/changing the kernel. So let's check the kernel 
module option? VFD brings some interesting capabilities, could it be a 
way to push and stimulate the i40e features instead of using DPDK?

for instance could be better stimulated.

Best regards,

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