Even faster VM networking with virtual passthrough
Channel: Andrea Ross
Date: 2015-06-17

by Giuseppe Lettieri

In past years, we have shown how to achieve very high networking speeds in bare metal and VMs using the netmap framework: embarrassingly high packet rates on bare metal, comfortably good on VMs through conventional device emulation techniques.

In this talk we show how to fill the speed gap between HW and VMs with a non conventional use of netmap, namely virtual passthrough. In this mode of operation, the guest VM uses directly the host's netmap port (thus saving extra data copies), while notifications are dispatched efficiently between guest and host.

Thanks to this technique we can achieve communication speeds between untrusted guests in the order of 20 Mpps, and reach 50 Mpps between trusted guests across netmap pipes.