Hi all,
today I have wanted to do hard vcpu pinning from the domU config file
and found life still does *all* it can to stay challenging.
Take a VM with 2 vcpus that should be hard-pinned to two physical CPUs.
We''ll use one core and one HT for this experiment.
One might try the following config.
vcpus = 2
cpus = [ "1", "5" ]
But this is in fact wrong. As we can see from xm vcpu-list this will
define two vcpus which are both runnable on cpu 1 or 5.
myvm 29 0 5 r-- 16.2 1,5
myvm 29 1 5 --- 13.9 1,5
Whereas a
xm vcpu-pin myvm 0 1
xm vcpu-pin myvm 0 5
in fact does the right thing
myvm 29 0 1 -b- 20.5 1
myvm 29 1 5 -b- 18.6 5
in xm list --long this is presented as following format:
(cpus (1 5))
And that entry doesn''t change when I do the hard pinning.
So, is this in fact impossble to specify from a domU config file?
Greetings,
Florian
--
the purpose of libvirt is to provide an abstraction layer hiding all
xen features added since 2006 until they were finally understood and
copied by the kvm devs.