[dpdk-dev] Reg DPDK & PMD

[Bruce Richardson]

On Wed, Mar 08, 2017 at 07:05:03PM +0530, raman geetha gopalakrishnan wrote:
> Hi All,
> 
> I have the following basic question. Hope to get an answer / link where i
> can get myself clear.
> 
> 1. In DPDK PMD is optimized driver for an given NIC to get maximum
> performance.
>     That being the case why we are talking about DPDK supported NICs.
> 
>      A) My assumption is that NIC interface is standardized so that PMD
> should actually work with any NIC (barring some NIC specific performance
> tweaks)
>           is that correct?

No, that assumption is not correct, which is the reason we have so many
NIC drivers in DPDK. Each NIC uses a different method of talking to SW,
both in terms of the registers needed to be accessed to initialize the
NIC and then in terms of the metadata format used to receive or transmit
packets.

Regards,
/Bruce

> 
>      B) if #A is correct , how can i make changes to PMD to support any NIC
> ?
> 
> if i have to put the above question in different way then it is
> 
> 2. what is preventing us from having a common PMD layer for all NICs and
> additional PMD specific to each NIC???
> 
> Thanks
> Raman