RSS related query for connectx vpi card


I am using Mellanox InfiniBand card and lspci command output is

InfiniBand: Mellanox Technologies MT25418 [ConnectX VPI PCIe 2.0 2.5GT/s - IB DDR / 10GigE] (rev a0)

It has two ports and both have been configured as Ethernet. The firmware version is 2.9.1314.

I have installed Mellanox ofed (MLNX_OFED_LINUX-2.0-3.0.0) and the OS platform is CentOS 6.4(2.6.32-358.el6.x86_64).

I have also enabled flow steering by passing module parameter log_num_mgm_entry_size=-1 to mlx4_core.

I have few queries related to this card:-

  1. Does this card support RSS and if it supports then what are the default flow keys (like source address, destination address etc.) being used for hashing in card. How to find out these flow keys?
  2. How can I change these flow keys using ethtool? Let’s say I want to use 3 flow keys for hashing (source and destination address and protocol field of layer 3) then what should be the ethtool command for this.

I tried some options with ethtool but I may be trying wrong options.

Thanks in advance


I believe that RSS is supported for your MT25418 (ConnectX-2) HCA. The documentation on RSS is a little thin unless I can’t find it. If you refer to you’ll see 2 references…


  1. Added UDP RSS support (on ConnectX-2 HW only).


  1. Added the usage of Toeplitz hash function for RSS calculation.


And, in the Mellanox_OFED_Linux_User_Manual_v2.0-3.0.0.pdf, page 222 of 224, under mlx4_en Parameters…

udp_rss: Enable RSS for incoming UDP traffic (uint). On by default. Once disabled no RSS for incoming UDP traffic will be done.

I don’t have any further information beyond this but I’ll do some digging…


Thanks Branko,

Yes, MT25418 supports RSS but still i am not able to find out the default flow keys which are used for creating flows and how to change these values. before posting my query i already had gone through the Mellanox_OFED_Linux_User_Manual_v2.0-3.0.0.pdf and MLNX_EN_relase_notes but i didn’t get any clue for my question related to flow keys(how to change and default flow keys).