0 Replies Latest reply on Apr 27, 2017 10:29 PM by cmyers

    mlx5/connectx-4 out of order packets w/ a single queue?

    cmyers

      Hi,

       

      I am writing packet generation/analysis software using the ConnectX-4 (mlx5) DPDK  driver.

       

      With all other NICs I have tried (including ConnectX-3) when only a single queue on an interface is used

      all packets are usually received in the order they are sent regardless of changing IP/MAC addresses

      because RSS is not being used.

       

      Is the ConnectX-4 doing  RX flow classification/analysis all the time which would cause this?

      Is there a way to turn it off?

       

      I am using DPDK 16.11 with Mellanox 4.0-1.5.2.0 kernel drivers w/ linux 4.4 kernel in a VM  running on QEMU/KVM w/ PCI passthru.

       

      ConnectX-4 EN

      Firmware: 12.18.2000

      Board ID: MT_2150110033

       

      Attached is a simple program which reproduces the issue.

      See the readme.txt file in the .tgz file for additional details and description of program.

       

      I thought the issue might be caused by the WQ indirection in the DPDK driver so I modified the

      DPDK mlx5 driver code to use a QP directly, but there are still out of order packet issues.

       

      Any idea why this is occurring?

       

      Thanks,

      Charles