Hi, I am using openstack wallaby on ubuntu 20.04 and kvm. I am working to make optimized flavor properties that should provide optimal performance. I was reviewing the document below. https://docs.openstack.org/nova/wallaby/admin/cpu-topologies.html I have two socket AMD compute node. The workload running on nodes are mixed workload. My question is should I use default nova CPU topology and NUMA node that nova deploys instance by default OR should I use hw:cpu_sockets='2' and hw:numa_nodes='2'. Which one from above provide best instance performance ? or any other tuning should I do ? The note in the URL (CPU topology sesion) suggests that I should stay with default options that nova provides. Currently it also works with libvirt/QEMU driver but we don’t recommend it in production use cases. This is because vCPUs are actually running in one thread on host in qemu TCG (Tiny Code Generator), which is the backend for libvirt/QEMU driver. Work to enable full multi-threading support for TCG (a.k.a. MTTCG) is on going in QEMU community. Please see this MTTCG project <http://wiki.qemu.org/Features/tcg-multithread> page for detail. Ammad