What does Enable single-root I/O virtualization (SR-IOV) do in Hyper-V? Enable single-root I/O virtualization (SR-IOV) is a Hyper-V External Virtual Switch setting that offloads to the emulated hardware, instead of virtualising it in Hyper-V as a software device (not physical).
There can be some performance advantages of enabling single-root I/O virtualization, but SR-IOV will probably make your network go slower because:
- Emulated devices requires lots of Hypervisor intercepts for every single I/O
- Operations can’t use shared memory access, which is faster
- Emulated devices require operations that are based on the hardware emulated functionality, whilst software devices can be programmed based on the required functionality of the software and are therefore faster
- There’s not need to transition through layers of the hypervisor to send commands with software devices, so conversely single-root I/O virtualization is slower