unexpectedly low throughput for VLAN tagged packets

[sarsanaee]

Hello,

We are generating some VLAN tagged packets using scapy, however, the QeueuOut throughput is considerably low, for example, our network is a 10G network but the output rate is about 25Mbps as per PMD port. It sends packets out at the line rate(10G) if we generate packets without any VLAN tags.

Is there any ideas about the root cause of this overhead, and what can be done to alleviate it? I just want to add that this only happens with Mellanox NIC MLX5!

Thanks in advance,
Alireza