[dpdk-dev] kni vs. pmd

[Jose Gavine Cueto]

Hi Pashupati,

Thanks for mentioning the extra copy.  But I couldn't grasp much about "I
look at KNI as more for control path operation and PMDs for data path" .
 Could you please give a simple example if you have time ?

Thanks,
Pepe


On Fri, Dec 13, 2013 at 7:07 AM, Pashupati Kumar <kumarp at brocade.com> wrote:

> > -----Original Message-----
> > From: dev [mailto:dev-bounces at dpdk.org] On Behalf Of Jose Gavine Cueto
> > Sent: Tuesday, December 10, 2013 3:16 PM
> > To: dev at dpdk.org
> > Subject: Re: [dpdk-dev] kni vs. pmd
> >
> > Additional question:
> >
> > Apart from the possible fact that kni performs zero-copy in the driver
> layer,
> > does this also apply on the sockets layer, or does the sockets
> operations (+
> > sys calls) are not avoided ?  This is assuming that the application uses
> regular
> > sockets to read/write to knis.
> If you are going to use KNI, there is a copy involved from iovec to RTE
> mbuf memory ( assuming you are going to use Ring library for communication
> between DPDK application and KNI). I look at KNI as more for control path
> operation and PMDs for data path.
> >
> > Cheers,
> > Pepe
> >
> >
> > On Wed, Dec 11, 2013 at 7:12 AM, Jose Gavine Cueto
> > <pepedocs at gmail.com>wrote:
> >
> > > Hi,
> > >
> > > Correct me if I'm wrong, but in a high-level perspective I see that
> > > kni is providing an option for applications to use their regular
> interfaces
> > (e.g.
> > > sockets) and abstracts the usage of pmds.
> > >
> > > If this is somehow correct, are there any differences with regard to
> > > performance benefits that can be brought between directly using pmd
> > > apis and kni ?
> > >
> > > I see that kni is easier to use, however at first (no code inspection)
> > > look, it interfaces with the kernel which might have introduced some
> > > overhead.
> > >
> > > Cheers,
> > > Pepe
> > >
> > >
> > > --
> > > To stop learning is like to stop loving.
> > >
> >
> >
> >
> > --
> > To stop learning is like to stop loving.
>
> Thanks
> Pash
>



-- 
To stop learning is like to stop loving.