[dpdk-users] low Tx throughputs in DPDK with Mellanox ConnectX-3 card

[Adrien Mazarguil]

Hi Zhilong,

On Tue, Jul 25, 2017 at 09:20:38PM +0800, zhilong zheng wrote:
> Hi Adrien,
> 
> Thanks for your reply and suggestion. I change the packet size to 128B, it can generate ~34Gbps and ~40Gbps while to 256B and larger.

OK, looks like it scales properly, I think you cannot get much more than
this with small packets.

> > 在 2017年7月25日，02:20，Adrien Mazarguil <adrien.mazarguil at 6wind.com> 写道：
> > 
> > Hi Zhilong,
> > 
> > On Sat, Jul 22, 2017 at 12:05:51AM +0800, zhilong zheng wrote:
> >> Hi all,
> >> 
> >> I have some problem when generating packets to the Mellanox ConnectX-3 dual 40G ports card from the latest pktgen-dpdk.
> >> 
> >> The problem is that it can only generate ~22Gbps per port (actually I just use one port.), not saturating the 40G port. This server has two 12-cores E5-2650 v4 @2.20GHz cpus and 128G 2400MHz DDR4 memory. The DPDK version is 16.11.
> >> 
> >> This is the driver bound to the NIC:   0000:81:00.0 'MT27500 Family [ConnectX-3]' if=p6p1,p6p2 drv=mlx4_core unused=
> >> I guess that it’s the problem of driver. The document shows the driver name should be librte_pmd_mlx4 (url: http://dpdk.org/doc/guides/nics/mlx4.html <http://dpdk.org/doc/guides/nics/mlx4.html>), however when completing installation, it’s bound to mlx4_core.
> > 
> > It's OK, mlx4_core is the name of the kernel driver while librte_pmd_mlx4 is
> > that of the DPDK driver. There is no librte_pmd_mlx4 kernel module, see
> > blurb about prerequisites [1].
> > 
> >> Any clue about this problem? And whether it’s caused by the driver or others?
> > 
> > Depending on packet size and other configuration settings, you may have hit
> > the maximum packet rate, these devices cannot reach line rate with 64-byte
> > packets for instance.
> > 
> > [1] http://dpdk.org/doc/guides/nics/mlx4.html#prerequisites
> > 
> > -- 
> > Adrien Mazarguil
> > 6WIND
> 

-- 
Adrien Mazarguil
6WIND