The speed of the router on Linux drops after virtualization Hyper-V

Problem:

The speed of the router on Linux drops after transferring the router from hardware (PC) to VM (Hyper-V 2019), the same PC.

Question:

What can I set up on Hyper-V/Linux to bring the speed of the router on the VM closer to the speed of the router on the hardware?

The test computers from different VLANs and the router are connected via optics to a 10G switch (HP ProCurve 6120XG).

I tested the speed using iperf3 (parameters -P 8 -t 60) between the test computers.

Linux on hardware ~8 Gbit/sec

Linux on VM (Hyper-V 2019) ~4 Gbit/sec

Hardware router:

CPU: i7-4790, 4 cores, 8 threads

RAM: 32Gb

NIC1/NIC2: HP Ethernet 10Gb 2-port 560SFP+ Adapter, 10.50.0.1 (VLAN171), 10.50.1.1 (VLAN172)

OS: Oracle Linux 8.10

Hyper-V Router (2019):

vCPU: 8 cores

ram: 16Gb

ethernet1: 10.50.0.1 (VLAN171) -> vSwitch171 -> NIC1

ethernet2: 10.50.1.1 (VLAN172) -> vSwitch172 -> NIK2

I tried changing the vSwitch settings on Hyper-V.:

• Disable the RSC
• Disable Large Send Offload (LSO)

The speed practically did not change.