[dpdk-users] Ref: Excluding certain Rx Queues from the RSS hashing algorithm

[dpdk-users] Ref: Excluding certain Rx Queues from the RSS hashing algorithm

[Joshi, Venkatesh]

Hi,

We use the following hardware/software in our product:

* CPU: Intel Xeon Silver 4210
* NIC: XXV710-AM2
* NIC Firmware: 7.3/8.0
* Linux Kernel version: 4.14
* DPDK version: 20.08
* vfio-pci driver

Our DPDK application runs on 7 CPU threads. We have initialized 7 Rx Queues - one for each CPU thread.

We want to use one of the queues exclusively for traffic that matches Flow Director rules.
And, we want that when the RSS hashing algorithm provides action as Enqueue - it should not use that queue during its computation.

Example: We initialize Rx Queues 0 to 6.
Out of this, we want that Rx Queue 0 to 5 be used in the RSS hash algorithm when the action is enqueue.
Rx Queue 6 should be kept out of the RSS hashing logic.

This is wrt the i40e driver.

Is this possible?

regards,
venkatesh

Re: [dpdk-users] Ref: Excluding certain Rx Queues from the RSS hashing algorithm

[Stephen Hemminger]

On Mon, 5 Apr 2021 03:10:21 +0000
"Joshi, Venkatesh" <venkatesh.joshi@hpe.com> wrote:

> Hi,
> 
> We use the following hardware/software in our product:
> 
> * CPU: Intel Xeon Silver 4210
> * NIC: XXV710-AM2
> * NIC Firmware: 7.3/8.0
> * Linux Kernel version: 4.14
> * DPDK version: 20.08
> * vfio-pci driver
> 
> Our DPDK application runs on 7 CPU threads. We have initialized 7 Rx Queues - one for each CPU thread.
> 
> We want to use one of the queues exclusively for traffic that matches Flow Director rules.
> And, we want that when the RSS hashing algorithm provides action as Enqueue - it should not use that queue during its computation.
> 
> Example: We initialize Rx Queues 0 to 6.
> Out of this, we want that Rx Queue 0 to 5 be used in the RSS hash algorithm when the action is enqueue.
> Rx Queue 6 should be kept out of the RSS hashing logic.
> 
> This is wrt the i40e driver.
> 
> Is this possible?
> 
> regards,
> venkatesh

The hashing logic relative to flow rules is confused in DPDK.
Have you tried programming two rules, one for the traffic you want, and the other at lower priority which
is a match any rule?

Also, fdir is deprecated in DPDK, please consider using rte_flow instead.