[libvirt-users] cpuset not affecting real pid placement

Andrey Korolyov andrey at xdel.ru
Thu Oct 18 19:32:11 UTC 2012

On Wed, Oct 17, 2012 at 12:54 AM, Andrey Korolyov <andrey at xdel.ru> wrote:
> Hi,
> At least on 0.10.2 setting a cpuset doesn`t match a real process
> placement - VM still consumes all available cores.
> VM config:
> .snip.
> <vcpu placement='static' cpuset='0-5,12-17'>12</vcpu>
> .snip.
> for cpuset in $(find /cgroup/cpuset/libvirt/qemu/vmid/ -name
> cpuset.cpus) ; do grep 0-5 $cpuset ; done
> got: empty responce, e.g. 0-23 in my setup
> expected: at least bounded vcpuX threads
> In neighbor 'cpu' group libvirt sets cfq weights just fine, so this is
> clearly a bug.

Oh, I was wrong in suggestion that libvirt using cgroups for task
pinning, nevermind please. There must be some issue with taskset which
does not prevent vm execution on all cores even if a specific set was
passed, I have wrongly thought it was because cpuset value remains
default in libvirt sub-cgroup.

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