[dpdk-users] Tx burst getting failed with Virtio driver

[Stephen Hemminger]

On Thu, 4 Apr 2019 13:01:16 +0530
Sharon <sharon.t at altencalsoftlabs.com> wrote:

> Hi,
> 
> With a dpdk based application inside GCP VM instance,
> it is observed that while sending UDP packets of length 1300 at around 6 
> Gbps rate, tx burst starts failing frequently.

Virtio (like all devices) can only transmit so fast.
If you transmit faster than the host can consume, the queue will get full
this shows up in DPDK when all transmit descriptors are used.

6Gbps is about 4.4 Mpps and the upper bound on virtio is usually about 1 to 2 Mpps
because of the overhead of host processing (vhost and linux bridge).