Networking extremely slow with Intel PRO/1000

[yardas]

I tested only NAT but it is probably similar in other modes.

Data flow of download (to guest) is mostly 40-50 kB/s no matter where the download originates from (including the VM host itself). Sometimes it peaks to MB/s but shortly it returns to 40-50 kB/s. Sometimes it is even slower.

The download speed returns to normal if GRO is disabled, i.e. the following command run in the guest fixes the problem:

# ethtool -K NIC gro off

I think if the GRO is broken in the driver it should be switched off by default. IIRC it was, but the problem started to manifest recently, so there may be an regression.

Host kernel: 4.4.6-300.fc23.x86_64

Guest kernel: 3.10.0-349.el7.x86_64

Virtualbox-5.0.16

[yardas]

The Host/Guest networking is even so slow.

[Aleksey Ilyushin]

Please try bridged attachment mode. You may get quite different results. When you use NAT the segmentation is done in our code, when you use bridged the GRO packet is supposed to be passed to the host kernel as is, given that GRO is enabled on the host adapter.

[Frank Mehnert]

Sems to be related to the guest Linux kernel version. Not so old kernels (at least 4.2.0 from Ubuntu/Wily and also 3.16.0 Debian/Sid) show this behavior. Thanks for the heads-up.

[Frank Mehnert]

Only VMs with I/O-APIC enabled were affected. The I/O-APIC implementation had bugs which were fixed in 5.0.22. These fixes should also fix the network performance issues.