The VM-Series firewall for KVM is a high-performance
appliance but may require tuning of the hypervisor to achieve the
best results. This section describes some best practices and recommendations
for facilitating the best performance of the VM-Series firewall.
By default, KVM uses a linux bridge for VM networking. However,
the best performance in a virtual environment is realized with dedicated
I/O interfaces (PCI passthrough or SR-IOV). If a virtual switch
is required, use a performance-optimized virtual switch (such as
Open vSwitch with DPDK).