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

Adrien Mazarguil adrien.mazarguil at 6wind.com
Mon Jul 24 20:20:26 CEST 2017

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

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