How to enable DCQCN on ConnectX-3 Pro

Infrastructure & Networking Adapters and Cables InfiniBand/VPI Adapter Cards
1

Hello, everyone.

In the community, I found the method to set the DCQCN parameters on ConnectX-4.

It writes “adjust the parameters under the path /sys/kernel/debug/kernel/mlx5/”.

However, the method could not be applied to ConnectX-3 Pro. And the path “/sys/class/net/device name/ecn” does not exist.

So how can I enable DCQCN on ConnectX-3 Pro?

Thanks.

2

Hi,

Please note that ECN/DCQCN is not supported on ConnectX-3.

We do support RoCE with PFC in ConnectX-3 Pro, you can refer to the following guides:

HowTo Configure RoCE v2 for ConnectX-3 Pro using Mellanox SwitchX Switches https://community.mellanox.com/s/article/howto-configure-roce-v2-for-connectx-3-pro-using-mellanox-switchx-switches

HowTo Run RoCE over L2 Enabled with PFC https://community.mellanox.com/s/article/howto-run-roce-over-l2-enabled-with-pfc

Recommended Network Configuration Examples for RoCE Deployment https://community.mellanox.com/s/article/recommended-network-configuration-examples-for-roce-deployment

Thanks,

Samer

3

Hi, Samer

Thank you for your help. I saw that the DCQCN paper (Congestion Control for Large-Scale RDMA Deployments) said ConnectX-3 implemented DCQCN in firmware. So I wonder how to enable it.

One more question, can I configure the DCQCN on the 100Gbps ConnectX-5 EN card like ConnectX-4? Actually, I could not find relevant documents for ConnectX-5 EN in the community.

Thank you.

4

Hi ,

Regarding ConnectX-5 it is the same as ConnectX-4:

HowTo Configure DCQCN (ECN) Parameters for Windows Driver (WinOF-2) https://community.mellanox.com/s/article/howto-configure-dcqcn--ecn--parameters-for-windows-driver--winof-2-x

This post illustrates how to set the DCQCN (ECN) parameters for WinOF-2 driver (ConnectX-4 and ConnectX-5 adapter cards).

HowTo Configure DCQCN (RoCE CC) values for ConnectX-4 (Linux) https://community.mellanox.com/s/article/howto-configure-dcqcn--roce-cc--values-for-connectx-4--linux-x

DCQCN Parameters https://community.mellanox.com/s/article/dcqcn-parameters

Regarding ConnectX-3 , DCQCN was not implemented in the firmware.

We recommend using the tested and verified solution RoCE with PFC for ConnectX-3.

Thanks,

Samer

5

Thanks, very helpful.