Re: [dpdk-dev] Reg DPDK & PMD

["Wiles, Keith" <keith.wiles@intel.com>]

> On Mar 8, 2017, at 8:25 AM, Ferruh Yigit <ferruh.yigit@intel.com> wrote:
> 
> On 3/8/2017 1:35 PM, 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?
> 
> PMDs (Poll Mode Drivers) are _real_ device drivers, they are not an
> optimization layer on top off a standardized interface, they deal
> directly with hardware, so needs to be specific to hardware.
> 
>> 
>>     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???

Another minor point is DPDK has a generic API layer for the ethernet NICs it is called ethdev with a set of standard APIs for the application. The PMDs attached themselves to the ethdev using standardized APIs, which is about as close we can get to a standard interface to PMDs/hardware.

>> 
>> Thanks
>> Raman
>> 
> 

Regards,
Keith