[dpdk-dev] [PATCH] examples/l3fwd: enable multiple Tx queues on a lcore

[Rong, Leyi]

> -----Original Message-----
> From: David Marchand <david.marchand at redhat.com>
> Sent: Wednesday, November 4, 2020 4:43 PM
> To: Rong, Leyi <leyi.rong at intel.com>
> Cc: Zhang, Qi Z <qi.z.zhang at intel.com>; dev <dev at dpdk.org>
> Subject: Re: [PATCH] examples/l3fwd: enable multiple Tx queues on a lcore
> 
> On Wed, Nov 4, 2020 at 9:34 AM Rong, Leyi <leyi.rong at intel.com> wrote:
> > > -----Original Message-----
> > > From: David Marchand <david.marchand at redhat.com>
> > > Sent: Wednesday, November 4, 2020 4:14 PM
> > > To: Rong, Leyi <leyi.rong at intel.com>
> > > Cc: Zhang, Qi Z <qi.z.zhang at intel.com>; dev <dev at dpdk.org>
> > > Subject: Re: [PATCH] examples/l3fwd: enable multiple Tx queues on a
> > > lcore
> > >
> > > If I count well, this is the v3 of the patch.
> > > Please version your patches.
> >
> > The previous versions are set to superseded. As nothing changes with
> > content on those versions, can start from this version?
> 
> The commitlog changes even if the code itself did not change, so this is a
> different patch.
> Different patches mean different versions.
> This shows that some work happened since the v1 submission.
> 

Agreed.
> 
> > As there always has thoughput limit for per queue, on some performance
> > test case by using l3fwd, the result will limited by the per queue
> > thoughput limit. With multiple Tx queue enabled, the per queue thoughput
> limit can be eliminated if the CPU core is not the bottleneck.
> 
> Ah interesting.
> Which nic has such limitations?
> How much of an improvement can be expected from this?
> 
> 
> --
> David Marchand

The initial found was on XXV710 25Gb NIC, but suppose such issue can happen on more NICs 
as the high-end CPU per core boundary is higher than many NICs(except 100Gb and above) per queue performance boundary.
The improvement can be about 1.8X with that case at 1t2q. 

Leyi