Re: DPDK with Mellanox ConnectX-5, complaining about mlx5_eth?

[Thomas Monjalon <thomas@monjalon.net>]

14/11/2024 17:10, CJ Sculti:
> I figured out the initial issue. For some reason, having both devices in a
> bond on the kernel results in only 1 of the two ports being exposed as
> 'verb' devices. Previously, ibv_devinfo returned only one port. After
> removing both from the bond, ibv_devinfo returns both ports, and the DPDK
> application successfully takes both in. I'm still having some weird
> behavior trying to create a bypass interface with these ports though. I'm
> using the same code that I've been using on my Intel NICs with igb_uio for
> years, but seeing weird behavior. The ports are connected to our 40Gbps
> Ethernet switch, and set to link_layer: Ethernet.

You should be able to make it work with kernel bonding,
but I'm not sure what's wrong to do that.
And it looks not a priority for you. Let's focus on the other parts.


> The first thing I noticed is that rte_eth_dev_reset() fails on these
> interfaces with "ENOTSUP: hardware doesn't support reset".

You don't need the reset procedure with mlx5,
so you can make this code optional.


> Secondly, when checking ptypes, I noticed my code says these NICs are
> unable to support any sort of packet detection capability (code below, all
> return false). The MLX5 docs do say that all of these ptypes used here are
> supported by MLX5.

The supported ptypes can be checked in mlx5_dev_supported_ptypes_get() code.
I don't understand why it does not work for you.


> I'm just picking up a project that was left off by an older dev. It hasn't
> been touched in years, but has been working fine with our Intel NICs. All
> I'm trying to do is update DPDK (which is done, updated from dpdk 19.05 to
> DPDK 22.11, latest version with KNI support),

You don't need KNI with mlx5.
That's a big benefit of mlx5 design, it is natively bifurcated:
	https://doc.dpdk.org/guides/howto/flow_bifurcation.html


> and get it to work with our Mellanox CX5 NICs.
> This is my first time working with DPDK and I'm not very
> familiar. Should I expect to be able to do this without having to make a
> ton of code changes, or is this going to be an uphill battle for me? If
> it's the latter, I will likely just go purchase Intel NICs and give up on
> this.

The NICs have difference that DPDK is trying to hide.
If something is not compatible you may consider it as a bug or a limitation.
I think you should try a bit more, we are here to help.