[dpdk-users] KNI drive without supported NICs?

[Lazarenko, Vlad (WorldQuant)]

Dumitru,

This clear things up a big time! Much appreciated. Thank you!

- Vlad

> -----Original Message-----
> From: Take Ceara [mailto:dumitru.ceara at gmail.com]
> Sent: Monday, February 06, 2017 6:05 AM
> To: Lazarenko, Vlad (WorldQuant)
> Cc: users at dpdk.org
> Subject: Re: [dpdk-users] KNI drive without supported NICs?
> 
> Hi Vlad,
> 
> On Sun, Feb 5, 2017 at 6:34 PM, Lazarenko, Vlad (WorldQuant)
> <Vlad.Lazarenko at worldquant.com> wrote:
> > Gentlemen and gentleladies,
> >
> > I am trying to get the KNI working on my dev box. So I've loaded the
> rte_kni.ko module and made sure /dev/kni has correct permissions. But
> when I am trying to run the KNI example, it fails with "No supported
> Ethernet device found" error:
> >
> > $ build/kni -n 4 -c 0xf0 -- -P -p 0x3 --config="(0,4,6),(1,5,7)"
> > EAL: Detected 24 lcore(s)
> > EAL: PCI device 0000:01:00.0 on NUMA socket -1
> > EAL:   probe driver: 8086:10d3 net_e1000_em
> > EAL: Error - exiting with code: 1
> >   Cause: No supported Ethernet device found
> >
> > My dev box does not in fact have supported NICs. But my understanding
> about KNI was that it allows to access Linux network stack trough the KNI
> kernel module, where applications create a virtual Ethernet devices (i.e.
> /sys/class/net/vEth*), thus there is no need for a real supported NIC or
> taking over the entire NIC.
> >
> > On the other hand, the example application calls rte_eth_dev_count()
> first, which in my case returns 0, and exits.
> >
> > Is my understanding about what KNI actually is wrong? Or am I missing
> something else?
> >
> 
> As far as I know the KNI sample app actually forwards traffic to/from the
> kernel and a physical port therefore the check for physical interfaces. If you
> want to use KNI for something else there's nothing stopping you from
> starting a DPDK app and adding a KNI interface without having a real NIC
> bound to DPDK.
> 
> I don't have a better example right now but, if you want, you can take a look
> at how we do it in warp17 (using DPDK) when you start it without any
> physical interfaces:
> 
> https://github.com/Juniper/warp17#using-kernel-network-interface-kni-
> interfaces
> 
> If you look at the HTTP example there we actually start the application
> without any physical interfaces (only one KNI):
> 
> ./build/warp17 -c FC3 -n 4  -m 32768 -- --kni-ifs 1
> 
> 
> > Thanks,
> > Vlad
> 
> Hope this helps..
> 
> Regards,
> Dumitru
> 
> >
> >
> >
> >
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> 
> 
> --
> Dumitru Ceara


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