I’m not sure what IFQ stands for, but Sepherosa Ziehau’s added it.  It appears to be based on an idea from Luigi Rizzo called ‘netmap‘.  In this case, network packets are grouped together before being placed onto the network interface’s hardware queue.  That means better packet per second performance without a corresponding increase in CPU usage, as Sepherosa Ziehau’s report lists, along with needed sysctls.