Sorry it this is a duplicate, but I believe that last time when I
replied I forgot to cc the mailing list. First of all, thank you for the
helpful info, but I have one more question!
How do I get the packets distributed to multiple queues without RSS? I
turned off RSS by setting ETH_MQ_RX_NONE. I configured multiple queues
to be used by QEMU and OvS. Inside my DPDK application I checked the
nb_rx_queues value inside the rte_eth_dev_info struct and it says I have
10 rx_queues and max_rx_queues for the virtio device that was bound to
the dpdk application, so at least this initial configuration seems to be
working and DPDK is detecting multiple queues. The issue I am having is
that I am only receiving packets in rx queue 0. From some other similar
questions it seems like that is the default and specified behaviour, so
how do I also get the other rx queues to be used? I found some vague
stuff about using the rte_flow API. I can see how the queue action can
be used to move packets to specific queues. These packets could even be
matched based on IP address and TCP ports, but I don't see how to
somewhat uniformly distribute them between queues without using a hash
and modulo operator (I believe the rte_flow API doesn't support that).
On 2023-07-28 16:12, Thomas Monjalon wrote:
Hello,
You can have packets distributed to multiple queues without RSS.
If you really wants to enable the RSS algorithms,
it seems not supported for now with vhost_user.
It can be enabled with vhost running in the kernel:
https://qemu.readthedocs.io/en/latest/devel/ebpf_rss.html
26/07/2023 00:58, Matheus Stolet:
Hello,
I am trying to run a DPDK application with RSS enabled so that I can
have multiple rx queues. This application is running inside a VM. This
VM is hosted by QEMU using KVM acceleration and OvS with DPDK and
vhost-user are used in the backend. So to clarify things there are two
DPDK portions to this. The first is the DPDK portion used by OvS that
bypasses the host operating system. This is working fine. The other is
a
DPDK application inside the virtual machine that will bypass the guest
operating system. This is where I am having trouble with.
When I set rte_eth_conf.rxmode.mq_mode = ETH_MQ_RX_RSS in my
application
I get the following errors:
Warning: NIC does not support all requested RSS hash functions.
virtio_dev_configure(): RSS support requested but not supported by
the
device
Port0 dev_configure = -95
I setup my VM in QEMU to have mq=on and queues=10. I also set the
number
of rx_queues when creating the vhost port using ovs to 10. Before
binding the interface to DPDK, I used ethtool to verify if the network
interface was actually setup to have multiple queues.
Running the 'ethtool -l enps02' command yields the following output:
Pre-set maximums:
RX: 0
TX: 0
Other: 0
Combined: 10
Current hardware settings:
RX: 0
TX: 0
Other: 0
Combined: 10
From my understanding the combined values indicate that the interface
was properly setup to have multiple queues, so why am I getting the
unsupported RSS error? Are there other configuration steps that I have
to take to get this to work? Is RSS with DPDK not supported at all
inside a VM at the moment? Perhaps the "Port0 dev_configure() = -95"
error means something else? Without the receive side scaling turned on
my application is not able to achieve the desired throughput and won't
scale when I assign more cores to the application.
Versions:
VM
DPDK: 21.11.4
Kernel: 5.4.0-148-generic
Distribution: Ubuntu 20.04
Host
DPDK: 21.11.4
QEMU: 8.0.90
OvS: 3.0.5
Kernel: 5.15.111.1.amd64-smp
Distribution: Debian 11
