Iommu

Kernel boot flags sorted into a host column and a guest column

Two Boot Lines — Which Kernel Flags Belong on a Proxmox Host, and Which Belong in the Guest

Most Proxmox tuning lines you find online are one blob of kernel flags. Half of them belong on the hypervisor, half belong inside the guest, two of the popular ones do nothing at all, and a few change meaning depending on which side of the boundary they land.

A curve rising from 36 percent of bare metal at queue depth 1 to within a few percent by queue depth 32

PCIe Passthrough Performance on Proxmox VE — The IOMMU Tax and How to Minimise It

Why PCIe devices lose throughput when passed through to a VM via VFIO, and the practical tuning steps that claw most of it back.