Answering to myself: the taskset needs to be applied to all guest threads, not
just the main process:ps -L -C kvm|awk '/kvm/ {print $2}'| xargs -n1 taskset -c
-p 0-7Thanks to Daniele for the info! The actual bug is because of certain AMD processors group cores in different NUMAs and the calculation of cores changed in libvirt. Newer libvirt should have this fixed. More discussion about the issue can be found e.g. here: https://bugzilla.redhat.com/show_bug.cgi?id=833425
