Comment 6 for bug 1856335

Damir, Example of how to use numa configuration.
-smp 16,maxcpus=16,cores=16,threads=1,sockets=1 -numa node,nodeid=0,cpus=0-7 -numa node,nodeid=1,cpus=8-15

This will help to put all the cores in correct L3 boundary. I strongly suggest to use the latest qemu release.