[dpdk-dev] Maximum possible throughput with the KNI DPDK Application

Malveeka Tewari malveeka at gmail.com
Thu Sep 18 06:55:45 CEST 2014


Thanks Helin!

I am actually working on a project to quantify the overhead of user-space
to kernel-space data copying in case of conventional socket based
applications.
My understanding is that the KNI application involves userspace -> kernel
space -> user-space data copy again to send to the igb_uio driver.
I wanted to find out if the 7Gb/s throughput is the maximum throughput
achievable by the KNI application or if someone has been able to achiever
higher rates by using more cores or some other configuration.

Regards,
Malveeka




On Wed, Sep 17, 2014 at 6:01 PM, Zhang, Helin <helin.zhang at intel.com> wrote:

> Hi Malveeka
>
> > -----Original Message-----
> > From: dev [mailto:dev-bounces at dpdk.org] On Behalf Of Malveeka Tewari
> > Sent: Thursday, September 18, 2014 6:51 AM
> > To: dev at dpdk.org
> > Subject: [dpdk-dev] Maximum possible throughput with the KNI DPDK
> > Application
> >
> > Hi all
> >
> > I've been playing the with DPDK API to send out packets using the l2fwd
> app
> > and the Kernel Network Interface app with a single Intel 82599 NIC on an
> Intel
> > Xeon E5-2630
> >
> > With the l2fwd application, I've been able to achieve 14.88 Mpps with
> minimum
> > sized packets.
> > However, running iperf with the KNI application only gives  me only
> ~7Gb/s
> > peak throughput.
>
> KNI is quite different from other DPDK applications, it is not for fast
> path forwarding. As it will pass the packets received in user space to
> kernel space, and possible the kernel stack. So don't expect too much
> higher performance. I think 7Gb/s might be a good enough data, what's your
> real use case of KNI?
>
> >
> > Has anyone achieved the 10Gb/s line rate with the KNI application?
> > Any help would be greatly appreciated!
> >
> > Thanks!
> > Malveeka
>
> Regards,
> Helin
>


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