best Practice #9: Tune for Latency-Sensitive Apps
So what is a virtual admin to do? Go back to the stone ages and make it a physical box—ha, no way!
With exclusive PCPU access given, each VCPU entirely owns a specific PCPU; no other VCPUs and threads (including VMkernel I/O threads) are allowed to run on it. This achieves nearly zero ready time and no interruption from other VMkernel threads, improving response time and jitter under CPU contention.
— Deploying Latency-Sensitive Applications in vSphere 5.5
Enabling an application for high latency sensitivity also helps with jitter, that is, it helps to reduce the jitter between packets and make each packet more consistent.
SR-IOV-capable devices provide configurable numbers of independent VFs, each with its own PCI Configuration space. The VMM assigns one or more VF to a virtual machine. Memory Translation technologies such as those in Intel® VT-x and Intel® VT-d provide hardware assisted techniques to allow direct DMA transfers to and from the VM, thus bypassing the software switch in the VMM. — Intel SR-IOV Primer