VMware ESXi 6.7 increased latency with NIC Passthrough



  • Greetings, I've noticed what I think is a suprising increase in latency when virtualizing PFsense on VMware ESXi 6.7. The hardware specs for both bare metal deployment and the virtualized deployment are the same. Does anyone else see this much of an increase in latency when virtualizing and using NIC passthrough?

    Specs:
    16GB DDR3 RAM
    Intel Celeron J3455 Processor (Quad Core, 1.5ghz)
    Intel I340-T4 Quad Port Gigabit NIC

    I've attached an fping/Netdata graph showing the latency increase both to the gateway and carrying through to other traffic leaving the firewall. I realize that virtualization is not free however, I was thinking that the NIC passthrough would eliminate a lot of the latency additions seen from virtualizing. I was surprised to see this much of an increase.

    In all cases shown on the graph, the PFsense box is using the same routes and has the same WAN IP address between bare metal and VM. The only thing changing on the graphs is the switch from a bare metal 2.4.4.p2 install to a virtualized 2.4.4.p2 install using NIC passthrough for LAN/WAN to the VM.
    0_1547646233441_bare_metal_VM_latency_comparison.png


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