Virt, DPDK cluster config: Enable AlignCPUs

In case the user's worker nodes have SMT [1] enabled,
they will probably encounter CNV-31584 [2].

Add an instruction to enable the `AlignCPUs` enabler
in HCO [3], so it will enable [4] KubeVirt to request
up to two additional dedicated CPUs in order to complete
the total CPU count to an even parity when using
emulator thread isolation.

[1] https://en.wikipedia.org/wiki/Simultaneous_multithreading
[2] https://issues.redhat.com/browse/CNV-31584
[3] kubevirt/hyperconverged-cluster-operator#2695
[4] kubevirt/kubevirt#10872

Signed-off-by: Orel Misan <[email protected]>

Author: orelmisan

modules/virt-configuring-cluster-dpdk.adoc

@@ -100,6 +100,20 @@ $ oc patch hyperconverged kubevirt-hyperconverged -n {CNVNamespace} \
 Editing the `HyperConverged` CR changes a global setting that affects all VMs that are created after the change is applied.
 ====
 
+. If your DPDK-enabled compute nodes use Simultaneous multithreading (SMT), enable the `AlignCPUs` enabler by editing the `HyperConverged` CR:
++
+[source,terminal,subs="attributes+"]
+----
+$ oc patch hyperconverged kubevirt-hyperconverged -n {CNVNamespace} \
+    --type='json' -p='[{"op": "replace", "path": "/spec/featureGates/alignCPUs", "value": true}]'
+----
++
+[NOTE]
+====
+Enabling `AlignCPUs` allows {VirtProductName} to request up to two additional dedicated CPUs to bring the total CPU count to an even parity when using
+emulator thread isolation.
+====
+
 . Create an `SriovNetworkNodePolicy` object with the `spec.deviceType` field set to `vfio-pci`:
 +
 .Example `SriovNetworkNodePolicy` manifest