I have an application where I configure multiple NICs with different PMDs and
then I have a simple poller thread that copies packets out of the descriptors
of configured NICs to dedicated rte_rings (one for each port) using
rte_eth_rx_burst. Other threads will then get packets out of the rings and
process packets on a per-port basis.

This poller is configured to run in realtime mode, with high priority on a
dedicated/isolated CPU. It works well and for example on an Intel X710 it can
process 10Gbps/1.8Mpps.

However, sometimes (like 3-4 times a day), the poller can't keep up and drops a
few packets. I have a sleep in my current configuration so I tried to remove it
and have the poller run in busy loop (since it runs in its own cpu and cpu
usage is not a problem). But if I do so, it starts dropping packets like crazy.
That's counter intuitive to me and I would like to know why that happens.