[dpdk-dev] Why IP_PIPELINE is faster than L2FWD

[Royce Niu]

Yes. One core is assigned.

On Fri, 23 Dec 2016 at 9:34 AM, Xu, Qian Q <qian.q.xu at intel.com> wrote:

> As far as I know, L2FWD only uses 1 core for all RX/TX, for all queues,
> but for ip_pipeline, you may use more cores.
>
> A simple question, are you using 1core in ip_pipeline or l3fwd test?
>
>
>
> > -----Original Message-----
>
> > From: dev [mailto:dev-bounces at dpdk.org] On Behalf Of Royce Niu
>
> > Sent: Thursday, December 22, 2016 9:36 PM
>
> > To: Richardson, Bruce <bruce.richardson at intel.com>
>
> > Cc: Royce Niu <royceniu at gmail.com>; dev at dpdk.org; Dumitrescu, Cristian
>
> > <cristian.dumitrescu at intel.com>
>
> > Subject: Re: [dpdk-dev] Why IP_PIPELINE is faster than L2FWD
>
> >
>
> > Dear Bruce,
>
> >
>
> > Thanks for your kind explanation.
>
> >
>
> > I will try to follow your suggestion and see the source code.
>
> >
>
> > On Thu, Dec 22, 2016 at 9:25 PM, Bruce Richardson <
>
> > bruce.richardson at intel.com> wrote:
>
> >
>
> > > On Thu, Dec 22, 2016 at 08:48:50PM +0800, Royce Niu wrote:
>
> > > > But, actually, L3FWD of IP_PIPELINE is also faster than stock L2FWD,
>
> > > which
>
> > > > also modifies mac addr. How can explain this?
>
> > > >
>
> > > > Actually, I want to know why IP_PIPELINE is much faster and I can
>
> > > > learn from IP_PIPELINE and make our own program.
>
> > > >
>
> > > > But, the documentation of that is not detailed enough. if it is
>
> > > > possible, could you tell me where is the key to boost? Thanks!
>
> > > >
>
> > >
>
> > > Adding Cristian as IP Pipeline maintainer.
>
> > >
>
> > > A lot of tuning work went into IP Pipeline and the table and port
>
> > > libraries it uses, so I'm not sure that there is just one or two key
>
> > > changes which give it such good performance. L2 forward just hasn't
>
> > > had the same level of tuning and, while performing well, is also
>
> > > simplified to make it understandable as an example. Contrast the code
>
> > > in l2fwd against equivalent vector code in l3fwd-lpm* files e.g.
>
> > l3fwd_lpm_sse.h.
>
> > > The latter is very high performing, the former is more readable.
>
> > >
>
> > > Regards,
>
> > > /Bruce
>
> > >
>
> > > > On Thu, Dec 22, 2016 at 7:15 PM, Bruce Richardson <
>
> > > > bruce.richardson at intel.com> wrote:
>
> > > >
>
> > > > > On Thu, Dec 22, 2016 at 12:18:12AM +0800, Royce Niu wrote:
>
> > > > > > Hi all,
>
> > > > > >
>
> > > > > > I tested default L2FWD and IP_PIPELINE (pass-through). The
>
> > > throughput of
>
> > > > > > IP_PIPELINE is higher immensely.
>
> > > > > >
>
> > > > > > There are only two virtual NICs in KVM. The experiment is just
>
> > > > > > moving packet from vNIC0  to vNIC1. I think the function is so
>
> > > > > > simple. Why
>
> > > L2FWD
>
> > > > > > is much slower?
>
> > > > > >
>
> > > > > > How can I improve L2FWD, to make L2FWD faster?
>
> > > > > >
>
> > > > > Is IP_PIPELINE in passthrough mode modifying the packets? L2FWD
>
> > > > > swaps the mac addresses on each packet as it processes them, which
>
> > > > > can slow
>
> > > it
>
> > > > > down. L2FWD is also more an example of how the APIs work than
>
> > > > > anything else. For fastest possible port-to-port forwarding,
>
> > > > > testpmd should give the highest performance.
>
> > > > >
>
> > > > > /Bruce
>
> > > > >
>
> > > >
>
> > > >
>
> > > >
>
> > > > --
>
> > > > Regards,
>
> > > >
>
> > > > Royce
>
> > >
>
> >
>
> >
>
> >
>
> > --
>
> > Regards,
>
> >
>
> > Royce
>
>