When you Nova boot an instance in an OSP Overcloud deployed using SR-IOV and CPU Pinning, that instance will be NUMA aligned, meaning that its vCPUs, memory, and SR-IOV VF (Virtual Function) will all be local to the same NUMA node. Nova will not allow you to deploy a non-NUMA aligned instance in such an environment (which you might want to do when testing the cross-NUMA penalty of your hardware).
If you are looking to misalign an instance for the purpose of testing, you can use the following process.
First, ssh to the Compute node running your test instance. In the example below, we can see that the libvirt shows VM three as being pinned to odd numbered cores. On this hardware that means, NUMA node 1.
In this example, our VM has 4 cores.
# virsh vcpupin 3
VCPU: CPU Affinity
Using “virsh vcpupin“ you can move the pinned VM cores to the pCPUs local to numa node 0.
In the example below, we start my migrating vCPU 0 to pCPU 12.
This article documents the configuration used to configure SR-IOV in OSP 8/Liberty on Dell hardware
Compute Node Configuration
This section will outline the changes needed to configure SR-IOV on each Compute Node.
Bios Configuration on Dell Compute Nodes
First, you will need to ssh to the drac of each Compute Node. Then, type the command below to enter racadm command line.
Type the command below to enable SRIOV.
#racadm set BIOS.IntegratedDevices.SriovGlobalEnable Enabled
RAC1017: Successfully modified the object value and the change is in
To apply modified value, create a configuration job and reboot
the system. To create the commit and reboot jobs, use “jobqueue”
command. For more information about the “jobqueue” command, see RACADM
Type the command below to verify your configuration.
This tells nova that all VFs belonging to the physical interface, “p1p1“, are allowed to be passed through to VMs and belong to the neutron provider network “sriov_net1” and all VFs belonging to the physical interface, “p3p1“, are allowed to be passed through for the network “sriov_net2“.
Restart nova-compute on each compute node with the command shown below.
#systemctl restart openstack-nova-compute
Install and Enable Neutron Sriov-Agent (Compute)
Note that the sriov-agent is not required, however, we are going to install and configure it anyway.