Bug#700445:
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 0-7
Thanks 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
Bug#700445:
I have the same problem after upgrading from squeeze to wheezy. Only the first half of the cores (4 out of 8) are visible to KVM host. I also have AMD processor on my HP Proliant DL165 G7 (AMD Opteron(tm) Processor 6136). The taskset workaround doesn't seem to help. The output of taskset indicates it changes the affinity list: # taskset -p -c 0-7 8755pid 8755's current affinity list: 0-3pid 8755's new affinity list: 0-7 but there is no change to the pinning of the cores: only cores 0-3 are used by KVM guest. Do I need to do something else to get the workaround working? Installed versions:linux-image-3.2.0-4-amd64: 3.2.46-1+deb7u1libvirt-bin: 0.9.12-11+deb7u1qemu-kvm: 1.1.2+dfsg-6
