Need help with mt7921au based adapter in a proxmox VM

[kinhsman]

Problem: I am encountering performance issues with mt7921au-based adapters when used in a Proxmox VM with USB passthrough. During iperf speed tests to a wired client on the same VLAN, I consistently achieve only around ~150 Mbps. I have moved the VM to my gaming Windows PC and run it via VMware workstation with a USB3.0 passthough, and the results are about the same

Hardware:

• Tested USB adapters: Fenvi FU-AX1800 and Comfast CF-953AX
• Proxmox hardware: Intel N100 CPU (4x core; 3.40 GHz)
• VM configuration: 1xCPU (host), 2GB RAM, USB 3.0 passthrough. I have also experimented with 4xCPUs with no improvement.
• Tested Operating Systems: DietPi OS (Debian based), OpenWRT

Comparison with Bare Metal Setup: When I ran the USB dongle on the same OS but in a bare metal setup (tested with a NanoPi R6S), I achieved optimal results of around ~650 Mbps.

Question: Has anyone successfully configured any of these adapters to achieve optimal results? While I'm aiming for approximately ~300 Mbps, the current speed of 150 Mbps is far from ideal. Any suggestions would be greatly appreciated.

[kinhsman]

Resolved: I have came across the following proxmox threads suggested to PCIe passthrough the entire USB controller instead of USB passthrough to get native speed https://www.reddit.com/r/Proxmox/comments/xks9dq/usb_passthrough_really_slow/ https://forum.proxmox.com/threads/how-do-i-add-an-entire-usb-controller-to-a-vm.113445/

I am now able to get 600Mbps after this change.

[ ID] Interval           Transfer     Bandwidth
[  4]   0.00-10.00  sec   101 MBytes  84.8 Mbits/sec                  sender
[  4]   0.00-10.00  sec   101 MBytes  84.8 Mbits/sec                  receiver
[  6]   0.00-10.00  sec  98.8 MBytes  82.8 Mbits/sec                  sender
[  6]   0.00-10.00  sec  98.8 MBytes  82.8 Mbits/sec                  receiver
[  8]   0.00-10.00  sec  97.4 MBytes  81.6 Mbits/sec                  sender
[  8]   0.00-10.00  sec  97.4 MBytes  81.6 Mbits/sec                  receiver
[ 10]   0.00-10.00  sec  96.4 MBytes  80.8 Mbits/sec                  sender
[ 10]   0.00-10.00  sec  96.4 MBytes  80.8 Mbits/sec                  receiver
[ 12]   0.00-10.00  sec  94.5 MBytes  79.2 Mbits/sec                  sender
[ 12]   0.00-10.00  sec  94.5 MBytes  79.2 Mbits/sec                  receiver
[ 14]   0.00-10.00  sec  92.6 MBytes  77.7 Mbits/sec                  sender
[ 14]   0.00-10.00  sec  92.6 MBytes  77.7 Mbits/sec                  receiver
[ 16]   0.00-10.00  sec  89.9 MBytes  75.4 Mbits/sec                  sender
[ 16]   0.00-10.00  sec  89.9 MBytes  75.4 Mbits/sec                  receiver
[ 18]   0.00-10.00  sec  86.6 MBytes  72.6 Mbits/sec                  sender
[ 18]   0.00-10.00  sec  86.6 MBytes  72.6 Mbits/sec                  receiver
[SUM]   0.00-10.00  sec   757 MBytes   635 Mbits/sec                  sender
[SUM]   0.00-10.00  sec   757 MBytes   635 Mbits/sec                  receiver

iperf Done.