UDP packet loss on guest

Discussions about using Linux guests in VirtualBox.
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4WheelsOff
Posts: 1
Joined: 9. Mar 2018, 20:13

UDP packet loss on guest

Post by 4WheelsOff »

I've been testing UDP packet throughput between my Linux guest (kernel 4.14.20) hosted on Windows 7 [VBox 5.2.8], and a physical Linux machine.

iperf3 reports no packet losses when sending 1400-byte UDP packets @ 350Mbps from the physical Linux machine (sender) to the Windows 7 host. However, when I send packets to the Linux guest VM, the reported packet loss is 3-5%. The guest uses bridged networking and the virtio-net driver. The iperf3 thread shows < 30% CPU load on one core. There are no other threads with significant load.

The Linux machine to Windows host test shows that the sender-to-host link is fine, so the loss is occurring somewhere between the host and guest. The virtio-net driver does not report any statistics (ethtool -S). Any ideas on how I can determine where the loss is occurring? I understand UDP delivery is not guaranteed, but at this data rate and load level, I wouldn't expect any packet loss at all.

Thanks.
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