[dpdk-users] qdisc errors on 20.11.1 & Azure

[Stephen Hemminger]

On Mon, 28 Jun 2021 07:36:12 -0400
"Tyler Blair" <tblair at fastmail.com> wrote:

> Hi,
> 
> I'm seeing what looks like benign errors from qdisc on testpmd & our DPDK app on Azure. I'm wondering if anyone knows of a way to 'fix' these?
> 
> EAL: Detected 8 lcore(s)
> EAL: Detected 1 NUMA nodes
> EAL: Detected static linkage of DPDK
> EAL: Selected IOVA mode 'VA'
> EAL: Probing VFIO support...
> EAL: VFIO support initialized
> EAL: Probe PCI driver: mlx5_pci (15b3:1016) device: 2a8d:00:02.0 (socket 0)
> EAL: Probe PCI driver: mlx5_pci (15b3:1016) device: 5ed7:00:02.0 (socket 0)
> net_vdev_netvsc: probably using routed NetVSC interface "eth1" (index 3)*
> *
> *tap_nl_dump_ext_ack(): Cannot delete qdisc with handle of zero**
> *
> *tap_nl_dump_ext_ack(): Failed to find qdisc with specified classid**
> *
> *tap_nl_dump_ext_ack(): Failed to find qdisc with specified classid**
> *
> *tap_nl_dump_ext_ack(): Failed to find qdisc with specified classid**
> *
> *tap_nl_dump_ext_ack(): Failed to find qdisc with specified classid**
> *
> *tap_nl_dump_ext_ack(): Failed to find qdisc with specified classid**
> *
> *tap_nl_dump_ext_ack(): Failed to find qdisc with specified classid**
> *
> *tap_nl_dump_ext_ack(): Failed to find qdisc with specified classid**
> *
> *tap_nl_dump_ext_ack(): Failed to find qdisc with specified classid*
> [...]
> 
> It's not causing any issues that I can see, I'm just wondering if there's a cause for this in the environment that we can fix so we don't have benign errors showing up.
> 
> Reproduced by running testpmd with no arguments on Azure:
> 
> - OS: Ubuntu 20.04 5.4.0-1048-azure
> - DPDK: 20.11.1 (LTS)
> - Networking: Azure Accelerated Networking (netvsc)
> 
> OS setup is pretty minimal, nothing special other than DPDK is installed.
> 
> I don't recall these errors happening while on bare metal - only on Azure.
> 
> Thanks!
> 
> Regards,
> Tyler

In order to support the tap flow emulation you need to hve the ingress qdisc
and the flower qdisc. Some of the Linux distros have packaged those into
kernels extras type packages.

Or just use netvsc PMD and avoid the problem.