Hello all, as you all probably know there are some issues around networking, yesterday I stumbled across another one, so I would like to summarize what should be adressed in future releases (highest priority first):
- latency 4.2.16 got better, but still there is a big difference in network latency using virtio or "virtual Intel". And still, even "virtual Intel" is 3-4 times slower than a real card or the same physical card on the host. Best performance can be achieved with a single virtual cpu and "virtual Intel cards". But if virtio would be a lot better quite some interrupts could be saved, see this: 16: 573 0 IO-APIC-fasteoi virtio0 17: 32 5799 IO-APIC-fasteoi eth2 18: 7886614 0 IO-APIC-fasteoi eth3 19: 11015 7671908 IO-APIC-fasteoi eth0 eth3, eth0 and virtio0 do basically the same network traffic. But as you can see the number of interrupts in virtio0 is next to zero compared to eth3 and eth0. Even if the interrupts were the same to achieve good latency virtio0 still would be a lot better to use probably. - SMP networking really suffers from using more than 1 virtual cpu for a guest. The latency gets a lot higher (though already a lot better in 4.2.16 than before) and the throughput performance drops _down_. Unfortunately there are quite some scenarios where more virtual cpu power is needed for the guest than one cpu can deliver. But e.g. using 4 virtual cpus makes networking unusable in production because of the very bad latency. - vlan if you have a box with igb (e.g. i350) physical network cards and your guest uses vlans you have a problem. The VLAN filter in intels' i350 driver and kernel 3.10.5 (and probably above) will filter out the incoming vlan tagged packets (outgoing works). You can work around this by vconfig the vlans needed on the _host_ interface (ifup is not needed). But that is not nice. It would be best if the vbox network kernel module would be able to inform the hosts' kernel about VLANs used by guests. If vconfig can, the module can do as well. -- Regards, Stephan _______________________________________________ vbox-dev mailing list [email protected] https://www.virtualbox.org/mailman/listinfo/vbox-dev
