Hardware Assisted Virtualized-I/O Messaging Analysis on Red Hat Enterprise Linux 6
The authors ran Red Hat Enterprise Linux 6.0 with KVM on a server using the Intel Ethernet Server Adapter X520-SR2, which can present up to 64 direct, virtualized network interfaces per port to the operating system and its guests via SR-IOV technology. PCI passthrough also provides direct connections between guests and the host's NIC, but can present only one interface per port. They tested the messaging performance of KVM guests in a configuration where standard PCI passthrough is not possible; that is, they use twice as many guests as there are network ports. For such a configuration, another network virtualization choice is to use a software bridge between the guest and the host's NIC.