Re: [Libvir] CPU pinning of domains at creation time
On Thu, 11 Oct 2007 09:00:14 -0400 Daniel Veillard wrote:
There are a few things I gathered on this issue. This affects
NUMA setups, where basically if a domain must be placed on a given cell
it is not good to let the hypervisor place it first with its own heuristics
and then later migrate it to a different set of CPU, but better to
instruct the hypervisor to start said domain on the given set.
That sounds good to me !
- For Xen it is possible to instruct the hypervisor by passing
(cpus '2,3') in the SExpr where the argument is a list of
the physical processors allowed
Yeah, we can set CPUs to the domain by passing that and
the physical CPUs will be pinned to VCPUs.
- for the mapping at the XML level I suggest to use a simple
extension
to the <vcpu>n</vcpu> and extend it to
<vcpu cpuset='2,3'>n</vcpu>
with a limited syntax which is just the comma separated list of
allowed CPU numbers (if the code actually detects such a cpuset is
in effect i.e. in general this won't be added).
How about adding <cpus>2,3</cpus> to the XML simply ?
And we may set 64 CPUs, it is hard to set all of them by each number.
(i.e. we have to set cpuset='1,2,3,4,5,6,7,8,9,10,....,64')
So I hope to use - (range) and ^ (negation) to set cpuset as Ryan said.
Regards,
Saori Fukuta