Re: [dpdk-dev] Using multi-queue with RSS on X540 VF

[Bruce Richardson <bruce.richardson@intel.com>]

On Sat, Dec 13, 2014 at 01:44:36AM +0000, Anant Mudambi wrote:
> Hi all,
> I am using DPDK 1.7.0.
> Qemu-KVM system with the Intel 10G X540 NIC; host has the Linux ixgbe PF driver and a guest is using a VF with the DPDK ixgbevf PMD (uio).
> I am trying to configure multiple (2 for now) receive queues on the VF and use RSS.
> I see packets coming only to queue 0 for some reason. Some questions about this:
> 
> 1] I see that most of the initial configuration to make multi-queue + RSS work is done in ixgbe_dev_mq_rx_configure()
>      [e.g. Setting up the redirect table and the MRQC register]. However, only the non-VF ixgbe_dev_rx_init() calls the above function;
>      ixgbevf_dev_rx_init() doesn't configure RSS-related hardware. Don't we need to do this configuration to use RSS on a VF?
> 2] Even after configuring the RSS-related hardware in ixgbevf PMD, packets only come to queue 0. I printed out the RSS-type and RSS-hash-value
>      fields from the write back Rx descriptor and they are both set to 0. So for some reason no RSS hash is being done for any packets.
> 3] Has anyone seen this kind of configuration work (multi-queue + RSS + VF)? I have an X540 NIC but has this worked on any other NIC for anyone?
> 4] Also any ideas on how to debug this problem further?
> 
> Thanks,
> Anant

RSS redirection of traffic in a VF is not supported by the hardware, so you are
pretty much stuck with all VF traffic going to queue 0. [Later hardware, such as
4x10G NICs e.g. "Intel® Ethernet Converged Network Adapters XL710" using the
i40e driver should support RSS with VFs]

/Bruce