In part 1, I discussed why Microsoft has been investing in SR-IOV for device I/O from virtual machines. The key points were to reduce latency, increase throughput, lower compute overhead, and for future scalability. Part two takes a look at SR-IOV from a hardware perspective.
For those who didn’t take up my offer of the light bed time reading of the SR-IOV specs (or don’t have access), let me summarize what SR-IOV is. And to be clear, when I say “SR-IOV”, take it to include closely associated specifications or additions to PCI Express specifications such as
- ATS (Address Translation Services) – A PCI Express Protocol that allows a device to fetch translations from an IOMMU (Input/Output Memory Management Unit).
- ARI (Alternate Routing Interpretation) – A PCI Express switch change and device change which allows a device to occupy more than eight RIDs on a single bus
- ACS (Access Control Services) – A PCI Express switch feature that forces peer-to-peer traffic upstream so that it can be translated by an IOMMU.
To learn more and to read the entire article at its source, please refer to the following page, Everything you wanted to know about SR-IOV in Hyper-V Part 2- John Howard's Blog - Senior Program Manager in the Hyper-V Team at Microsoft