Tuning Performance with SR-IOV

When SR-IOV is enabled in Hyper-V, the following steps can help to improve performance between VM to VM and VM to Host.

From host OSes on both Host 1 and Host 2:

1. Enable RSS on the PF and vSwitch:

   Enable-NetAdapterRss -name "ADAPTER_NAME"
   

2. Enable 4 queues per VF:

   Set-VMNetworkAdapter -VMName "YOUR_TEST_VM_NAME" -IovQueuePairsRequested 4
   
   Get-VmNetworkAdapter -VMName * | where {$_.SwitchName -eq "YOUR_TEST_SWITCH_NAME"} |
     Set-VmNetworkAdapter -IovQueuePairsRequested 4
   

3. Ensure the VMs have at least twice as many vCPUs as RSS queues. In this case, set the number of total processors in the VM to 8. To do this:

   1. Turn off the VM.

   2. In the VM, click Settings.

   3. Under Hardware, select Processor.

   4. Change the value of Number of virtual processors to 8.

   5. Apply the change.

4. For Windows Server 2022, issue the following command while the VM is in the off state:

   Set-VMProcessor -VMName "YOUR_VM_Name" -HwThreadCountPerCore 1 -Count 8
   

In both guest OSes VM1 and VM2:

1. Set RSS queues to 4 for all VFs in the guest OSes:

   Set-NetAdapterRss -InterfaceDescription *adaptive* -NumberOfReceiveQueues 4
   

2. Update the number of queues in the guest OS:

   Set-NetAdapterAdvancedProperty -Name "your_adapter_name_from_guest_os" -DisplayName
   "Maximum Number of RSS Queues" -DisplayValue "8 Queues"